Is there a correlation or cause-effect relationship between attractiveness and feet?

Is there a correlation or cause-effect relationship between attractiveness and feet?

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My psychology professor is very hard to understand and can't speak English well. She was saying something about a study was done that found the best indicator of a physical attractiveness is feet, and that men preferred small feet and women prefer large feet. Does anyone know the study being referred to? I can sort of see what is being said, as perhaps women are attracted to tall men and there's a correlation between height and foot size. What confuses me is my prof was definitely saying something about "the best indicator" as if the most attractive part of a person is their feet. Can someone provide a reference to such a study?

This is a weird one! Looks like your professor's on to something. Holmes' (2010) New Scientist article, "Why men are attracted to women with small feet" gives an interesting intro based on Atkinson and Rowe (2010), which was a rather hard-to-track-down poster (not that I've retrieved the original). They produced facial composites of eight women each based on longest and shortest foot length, and other composites based on other measurements, and had men rate their attractiveness. Composites look something like:

(source: (Not sure which measurement was the criterion used for these two.)

As a dude myself, I guess I'd rank the left composite as more attractive, but opinions vary, and it's worth noting that both benefit from a basic effect of facial composites: they reduce asymmetries and increase normativity, which are attractiveness enhancements, speaking basically, objectively, and generally. In any case, hopefully this demonstrates the research method clearly enough.

Atkinson and Rowe found that about 7 out of 9 men preferred the composite formed from the faces (i.e., not displaying the feet!) of the eight women with the shortest feet over the composite of the eight with the longest feet. This isn't support for the "best indicator" status though. Composites based on thigh length demonstrated favor for women with long thighs in 8 out of 9 men, and 11 out of 12 men prefer a composite of narrow-hipped women! That one surprised me a bit. Better indicators out there, it seems. Holmes doesn't mention any results from Atkinson and Rowe regarding male foot length, but long torsos and small wrists seem more noteworthy, at least in terms of their relationships with attractive male faces.

For an original article on foot length and attractiveness, check out Voracek, Fisher, Rupp, Lucas, and Fessler (2007). There's quite a story to tell here, it seems to have everything you're looking for, and Fessler is hosting the article for free access, so I'll just hook you with an excerpt of the abstract:

Relative foot length was smaller in young, nulliparous, and slim women… A vast majority of both men and women favored small feet in women, but large feet in men. One's own foot size appeared to correspond to evaluations of attractiveness; particularly, women with small feet preferred small feet in women in general. The preference for small feet in women was convergent across different methods of evaluating attractiveness.

- Atkinson, J., & Rowe, M. (2010, June 17). Pretty women have petite feet: An EP analysis of the homo sapiens skeleton. Poster presented at the 22nd annual meeting of The Human Behavior and Evolution Society. Eugene, OR, USA: University of Oregon.
- Voracek, M., Fisher, M. L., Rupp, B., Lucas, D., & Fessler, D. M. (2007). Sex differences in relative foot length and perceived attractiveness of female feet: Relationships among anthropometry, physique, and preference ratings. Perceptual and Motor Skills, 104(3), 1123-1138. Retrieved from

Examining the relationship between cohesion and return to team in elite athletes

Within an activity setting, perceptions of cohesion have been linked with individual membership both within the group (e.g., attendance) and outside the original context of the group (e.g., intention to return to the group in the future). However, research has yet to examine whether perceptions of cohesiveness within the group would be associated with the return of individuals to a group after it has disbanded.


The purpose of the present study was to examine the relationship between perceptions of team cohesion assessed in one season to the actual return of the players to the team for the following season.


Elite male ice hockey players (N = 122) on 8 teams completed the Group Environment Questionnaire to assess cohesion. Team rosters were examined the following season to determine the players who did and did not return to their teams.


Discriminant function analysis revealed that players who returned to play for the team in the following season held significantly greater perceptions of task cohesion, with the function accounting for 16% of the variance in actual return and correctly classifying 70% of the participants.


These results extend research on the cohesion/intention to return relationship to the actual return of individuals to a previous group.

✔️ How to Choose a Good Cause and Effect Topic

Do you already have a subject to write about? Check out our cause and effect essay ideas below, get inspiration to narrow down your topic.

In case you are free to choose a subject, here are some ways to get started. Remember that the cause and effect essay can be about anything. The major challenge is to thoroughly describe the causal relationships and demonstrate each cause and effect’s role.

Choosing a Topic: Best Tips

  • Think of some article you’ve read recently. It can be anything that picked your interest: news, scientific text, discussion of some issue, social media post, etc. What was the main subject there?
  • Remember any issue you’ve discussed with someone. Maybe you had a dynamic discussion that you can use for the beginning.
  • Scroll through your news feed. There must be something attracting your attention: Economics? Politics? Culture? Just choose the sphere that will be your starting point.
  • Research field of your interest. Think of what you are fond of, something not related to your studying. It can also be a good inspiration source.

All these can help to get to the final topic. In the beginning, the critical task is to depict a field of your interest and search it for the cause-effect scenarios. Examples of how to line up the question are below.

The Book of Why

  • Our technological and scientific society can be attributed to one question: why?
  • The brain is the most advance tool for managing causes and effects.
  • One issue with the way we write equations is that it doesn’t capture the cause-effect relationship between variables.
  • E.g. The barometer reading tracks the atmospheric pressure and we can describe this relationship as B = kP. However, we can rearrange the equation in many ways like k = B/P or B - kP = 0. This doesn’t capture the cause-effect between barometer and atmosphere though.
  • The current trend of big data is misleading in its intelligence because it can’t answer why questions.
  • Calculus of causation: causal diagrams and a symbolic language.
  • Causal diagrams: dot-and-arrow diagrams with dots as quantities and arrows as causal relationships.
  • Diagrams are the language of knowledge while symbols are the language of queries.
  • E.g. P(L | do(D)) what is the probability (P) that a patient would survive L years if made to take drug D?
  • This is different from the conditional probability of P(L | D).
  • The difference between seeing and doing.
  • Counterfactual reasoning: dealing with what-if situations.
  • Counterfactuals may seem unscientific because of the lack of evidence but people commonly perform this type of reasoning.
  • E.g. If the rooster is silent, we know the Sun will still rise. The rooster doesn’t cause the sun to rise, but rather the other way around.
  • You can’t answer a question that you can’t ask, and you can’t ask a question that you have no words for.
  • We think of a cause as something that makes a difference, and the difference it makes must be a difference from what would have happened without it.
  • Summary of the book’s message: you are smarter than your data.

Chapter 1: The Ladder of Causation

    The difference between a “what” question and a “why” question: what provides facts, why provides explanations.

Three implications of this distinction

  • The world isn’t made up of facts but of the cause-effect relationship between these facts.
  • Causal explanations make up the bulk of our knowledge.
  • The transition from processors of data to makers of explanations is not small.

Three distinct levels of cognitive ability

The three levels are also known as the Ladder of Causation.

Chapter 2: From Buccaneers to Guinea Pigs: The Genesis of Causal Inference

  • Where regression to the mean is concerned, there is no difference between cause and effect.
  • Story of Pearson and how correlation came to dominate statistics.
  • The next story is about how Wright connected correlations (rung one) to hidden causal quantities (rung two).
  • Wright connected them using a method called path analysis.
  • “Correlation doesn’t imply causation” isn’t quite true, some correlations do imply causation.
  • Arrows omitted in a causal diagram actually convey more significant assumptions. An omitted arrows says the causal effect is zero while a present arrow says the causal-effect is something, just not zero.
  • The combination of knowledge of correlations with knowledge of causal relations is different from the deduction of causal relations from correlations.
  • Causal analysis incorporates some understanding of the process that produces the data, and then we get something that wasn’t in the data to begin with.
  • Path analysis shouldn’t be stereotyped, it isn’t a brain-dead method but requires domain-knowledge about the problem.
  • Causal analysis requires the user to make a subjective commitment. A causal diagram reflects the users qualitative beliefs.

Chapter 3: From Evidence to Causes: Reverend Bayes Meets Mr. Holmes

  • A causal diagram is a Bayesian network in which every arrow signifies a direct causal relation.
  • Bayes rule let’s us inverse probabilities, to find causes from effects.
  • E.g. Say we have a pool table of length L and we want to know the probability that a ball stops within x feet of the end. The intuitive probability is x / L.
  • However, what if we asked the reverse. Say the ball lands 1 foot from the end of the table (x = 1), then what is the probability that L is 100 feet?
  • Why is the forward probability (x given L) so much easier to assess mentally than the reverse probability (L given x)?
  • The asymmetry comes from the fact that L acts as the cause and x acts as the effect.
  • E.g. If Bob throws a ball at a window, the window will break. But if the window is broken, we need much more information to deduce the cause.
  • Bayes’s rule is also a way to update our belief in a hypothesis. Future events rests on the frequency with which similar events have occurred in the past.

Three types of junctions in a Bayesian network

  • Chain junction.
  • B is a mediator.
  • E.g. Fire → Smoke → Alarm
  • Although we call them fire alarms, they’re really smoke alarms.
  • Fork junction.
  • B is a confounded.
  • A confounded will make A and C statistically correlated even though there isn’t a causal link between them.
  • E.g. Shoe Size ← Age of Child → Reading Ability

Chapter 4: Confounding and Deconfounding: Or, Slaying the Lurking Variable

  • Confounding bias: when a variable influences both the cause and the effect.
  • Randomized controlled trial (RCT): an experiment where the group is randomly split into a test group and control group.
  • The whole art and practice of scientific experimentation is comprised in the skillful interrogation of Nature.
  • Nature is like a genie that answers exactly the question we pose and not necessarily the one we intend to ask.
  • It eliminates confounded bias by asking Nature the right question.
  • It enables researchers to quantify uncertainty.

Chapter 5: The Smoke-Filled Debate: Clearing the Air

  • The author details the story of how smoking was discovered to cause lung cancer and the start of how statistics isn’t enough.
  • There was an unresolved paradox in the mid-1960s where a mother who was smoking seemed to provide a benefit to underweight babies.
  • The proposed causal chain was: Smoking → Low Birth Weight → Mortality.
  • The low birth weight babies of smoking mothers had a better survival rate than those of non smokers.
  • However, the actual causal chain is: Smoking → Birth Weight ← Birth Defect → Mortality.
  • This path is non-causal because one of the arrows is the wrong way.
  • This is a case of the collider bias.

Chapter 6: Paradoxes Galore!

  • There’s a large class of paradoxes that reflect the tension between causation and correlation.
  • Human intuition operates under causation while data operates under probabilities.
  • The lesson from the Monty Hall problem is that the way we obtain information is as important as the information itself.
  • Any hypothesis that has survived some test that threatens its validity becomes more likely.
  • Our brains are not prepared to handle causeless correlations.
  • Conditioning on a collider means to filter the collider variable and find a correlation between the two colliding variables.
  • E.g. Have you noticed that among the people you date, the attractive ones tend to be jerks? That’s because you’ll date a mean attractive person, a nice unattractive person, and a nice attractive person, but not a mean unattractive person.
  • By self-selecting for what you want, you’ve introduced an implicit correlation.
  • Bad-Bad-Good Drug (BBG): a paradox where a drug is bad for one group, bad for another group, but is good for a combination of the groups.

Chapter 7: Beyond Adjustment: The Conquest of Mount Intervention

  • The author details the attempts to replace the do operator and it’s possible under three conditions.
  • Randomization is a great way to ensure that a variable isn’t affected by any confounders.
  • Introducing the idea of instrumental variables.
  • Monotonicity: there isn’t a case where Z is 0 and X is 1 aka someone that obtained the drug but wasn’t assigned it.

Chapter 8: Counterfactuals: Mining Worlds That Could Have Been

    We can’t travel both roads and yet our brains are equipped to judge what would’ve happened if we had taken the other path. Evidence if this comes in the form of regret.

Summary of lessons from the second rung

  • RCTs are the gold standard.
  • If we can measure variables that block all the back-door paths, we can use the back-door adjustment formula.
  • If we find a front-door path that’s shielded from confounded, we can use the front-door adjustment.
  • If we assume linearity or monotonicity, we can use instrumental variables.

Three different types of causation

  • The first key point is that experience depends on education since time spent on education is time not spent gaining experience.
  • The table doesn’t capture this data so we start with a causal diagram.
  • If experience was a cause of education, then experience would be a confounder and matching based on experience would be valid.
  • But the diagram shows experience as a mediator so we must not adjust it.
  • Don’t mistake a mediator for a confounder.
  • Abduction: use the data to estimate the factors unique to each employee.
  • Action: use the do operator to change the model to reflect the counterfactual assumption being made.
  • Prediction: calculate the new salary using the modified model and the updated info about exogenous variables.

Chapter 9: Mediation: The Search for a Mechanism

The question “Why?” has at least two versions.

  • One where you see an effect and you want to know the cause.
  • One when you want to better understand the connection between a known cause and a known effect.

Chapter 10: Big Data, Artificial Intelligence, and the Big Questions

What Does a Correlation Coefficient of Zero Mean?

Researchers find comparisons fascinating. A positive correlation is seen when variables move in the same direction, such as increased consumption of ice cream on the hottest days of summer.

A negative correlation occurs if a dramatic increase in the price of ice cream is associated with fewer sales and lost revenue. A zero coefficient would imply that ice cream sales in grocery stores do not rise or fall with outdoor temperature changes or price fluctuations, for instance.

Methodology of study

Well-being measurement

Different ways of measuring well-being reveal different contributing factors. The correlation between two of these, life satisfaction and happiness, in the World Values Survey (1981–2005) is only 0.47. These are different, but related concepts which are used interchangeably outside of academia. Typically, life satisfaction, or evaluative wellbeing is measured with Cantril’s self-anchoring ladder, a questionnaire where wellbeing is rated on a scale from 1–10. Happiness or hedonic/Affective well-being measurement is measured with the positive and negative affect schedule (PANAS), a more complex scale.


The UK Government’s Department of Health compiled a factsheet in 2014, in which it is stated that the key limitations to well-being, quality of life and life satisfaction research are that:

  • There are numerous associations and correlations in the body of evidence, but few causal relationships, since existing longitudinal datasets “do not use consistent wellbeing and predictor measures at different time points
  • After controlling for mental health status, not many of the found associations are still significant
  • Subgroup analyses are rare
  • There are too few studies to conduct meta-analyses
  • There are too few interventional studies.


The aim of this descriptive correlation study was to determine the effects of computer games addiction on physical and mental health of male and female students of guidance schools in Isfahan city.

The study population includes all students in the second year of public guidance schools in Isfahan city in the educational year of 2009-2010. The sample size includes 564 students selected by multiple steps stratified sampling method. Data were collected by using General Health Questionnaire (GHQ-28) scale and a questionnaire on addiction to computer games. To do this research, at first 3 districts (2-4) were selected randomly among five districts of Isfahan Board of Education. From each district, one boy and one girl guidance school was chosen randomly. In total, 600 students were chosen for filling the questionnaires, after obtaining the permission from Isfahan Board of Education. The questionnaires distributed among sample. 564 students filled the questionnaires and returned to the researcher.

The data collection instrument was included the form of GHQ-28 inventory of physical and psychological health measurement. Another tool was Antwan's (2008) questionnaire for addiction to computer. The Cranbach's alpha was reported 0.92 by this researcher,11 since the validity and reliability of this questionnaire was not assessed for Iran 30 students were selected as sample for a pilot study and after data analysis, and the reliability was measured 0.76. This questionnaire was based on Lickert scale and scored from 1 to 5. 1was for very little and 5 score was considered for very much.

The GHQ 28 inventory is created by Goldberg (1972) for diagnosing psychological disorders in various centers and environments. The questions are about the psychological condition in past month, including signs such as thought, abnormal emotions and dimensions of behavior that are observable. Therefore, questions emphasize on the situation (here and now). This questionnaire is the most known instrument for screening in psychiatry, and has a significant effect on developing researches. This questionnaire is in forms of 30. 60. 12 and 28 questions.11

The GHQ-28 which is used in this study was standardized by Palahang12 (2005) and Yaqubi (2005)13 in Iran. This questionnaire was used to assess health signs including physical complain, sleep disorder, disorder of social functioning and depression.

Errors in Correlation, Causation

Causation can masquerade as a number of other effects:

  1. Coincidence: Sometimes random occurrences appear to have a causal relationship.
  2. Deductive Error: There is a causal relationship, but it’s not what you think.
  3. Codependence: An external influence, a third variable, on the which two correlated things depend.

Errors of codependence result from an external stimuli that affects both datasets equally. Here are some examples.

Math scores are higher when children have larger shoe sizes.

Can we assume larger feet cause increased capacity for math?

Possible third variable: Age children’s feet get bigger when they get older.

Enclosed dog parks have higher incidents of dogs biting other dogs/people.

Can we assume enclosed dog parks cause aggression in dogs?

Possible third variable: Attentiveness of owners pet owners might pay less attention to their dogs’ behavior when there is a fence around the dog park.

Satisfaction rates with airlines steadily increase over time.

Can we assume that airlines steadily improve their customer service?

Possible third variable: Customer expectations customers may have decreasing expectations of customer service over time.

The burden of proof is on us to prove causation and to eliminate these alternative explanations.


Stress and personality are not only known to contribute to the progression of visual pathology, but they also influence patients’ ability to adapt to vision loss and quality of life [36]. Though our clinical experience is that psychosocial factors influence the extent of recovery, i.e., if a given patient will be a responder or non-responder, there is no empirical study of this potential relationship. Though the number of reports on vision restoration by different therapies (e.g., vision restoration training, ACS) is steadily increasing, their outcome is still highly variable. We urgently need to learn more about the role of physiological, psychological, and demographic factors that contribute to recovery of neurological functions in general and recovery of vision specifically. In the present study, we therefore analyzed the demographic and psychosocial profiles of a small convenience sample of patients suffering from vision loss, in which vision recovery was induced by ACS, a method known to improve visual fields [11, 12]. As we report here, age and gender did not affect vision recovery, while psychosocial factors (personality profiles) and physiological signs of VD had a profound influence on vision recovery. Specifically, “low stress personality” traits, i.e., lower neuroticism and greater conscientiousness, were positively correlated with vision recovery after ACS treatment as did some individual items of greater agreeableness and greater openness. In addition, we found that greater recovery was observed in patients with physiological signs of VD, a hallmark of FS [30].

In contrast to our original hypothesis, our correlations suggest that “stress-prone” personalities benefited (recovered) less from ACS and those with Flammer signs recovered more. Surprisingly, stress questionnaire profiles did not correlate at all with vision recovery. This may be due to a notable limitation of our study, namely, that our questionnaires were filled out by the patients long after the therapy had ended. Therefore, we cannot be certain about the cause-effect relationship. Though personality is considered a rather stable trait, vision loss, known to induce stress and reduce quality of life, may also have a profound influence on a person’s response in psychological questionnaires, which were collected several months or years after the therapy. Therefore, the following two possibilities exist: (i) either patients with a stress-prone personality respond less well to the therapy, or (ii) those who profited most from the therapy scored less neurotic and more conscientious as a result of a more optimistic outlook on life. In more simplified words, stress can either prevent recovery, or the experience of recovery leads to a fundamental personality change characterized by less stress, and a more optimistic, less neurotic, and more conscientious mental state. Which of these two possibilities is true, i.e., the nature of the cause-effect relationship, can only be answered in future prospective studies.

However, it is interesting to note that patients with FS signs of VD experienced greater recovery. Hence, this finding is compatible with the hypothesis that ACS, known to improve blood flow [21, 56], improves vision by way of normalizing blood flow. If this is confirmed by prospective studies, this would support our earlier proposal that neurological recovery is—at least in part—due to the normalization of blood flow. In this case, VD may be both a problem and a solution for neurological dysfunction: impaired autoregulation is a cause of neuronal inactivation and functional loss, and improvement of autoregulation is a major underpinning for recovery [22].

While our retrospective study should be interpreted with caution, our results support the notion that psychosocial factors and stress play an important role in neurological recovery. This is compatible with prior studies.

Personality, stress, and restoration of vision

Clinical experience and prior studies already suggest that mental stress is one of the main causes of vision loss, and a patient’s personality might lead to—or be affected by—stress. This was reported, for example, by Fontana [57] who found a significant negative correlation between stress and extraversion. They used the Professional Life Stress Scale (PLSS) to assess teachers’ stress levels and correlated it with personality dimensions as measured with the Eysenck Personality Questionnaire (EPQ). They observed significant positive correlations between stress and high scores of psychoticism and neuroticism, with neuroticism being the best predictor of stress levels, with age or gender having little influence. This supports our assumption that in low vision patients stress and personality traits are related.

Personality and vision recovery

It is conceivable that personality can have two different influences on visual performance and recovery: On one hand, it may have an influence on the actual performance during a testing session (state), or, on the other hand, it can be a stable, physiologically relevant influence of overall mental stress and stress hormone levels, which may last over months and years, impairing blood flow and neural function (trait).

In our study, we identified at least two out of five personality traits (neuroticisms, conscientiousness) to be significantly correlated with vision recovery. Specifically, patients who benefited from the ACS therapy were calmer, more peaceful and safer, more diligent, reliable, and organized in their lives. In addition, a single-item correlation of two other personality traits (openness, agreeableness) confirmed the overall finding.


Regarding the personality factor neuroticism, we found a significantly negative correlation with recovery. Neuroticism was studied in low vision patients also by Gaynes et al. [58] who evaluated if this personality trait is associated with decreased ability to adapt to change and that this modifies the association of vision impairment and cognition. Visually impaired subjects with high neuroticism had also a lower cognitive score than those with a low neuroticism level. Others [59,60,61] found that neuroticism was associated with decreased attentional control over the visual field, and it was proposed that neuroticism decreased attentional disengagement. We showed that lower neuroticism correlated significantly with vision recovery, but a prospective study with a larger sample should establish the cause-effect relationship.


High scores in this trait characterize persons who are self-disciplined, thoughtful, and goal-driven. It also indicates effort and super-ordinate control [60] which, in turn, affects social performance, such as academic achievement [61] and work engagement [62]. Individuals with high scores in conscientiousness are those more concerned with tasks and goals in the face of irrelevant information [60]. We found that higher scores positively correlated with vision recovery.

FS and vision recovery

Besides having demonstrated the correlation of personality and recovery, we also assessed how absolute and relative recoveries of visual functions relate to the severity of FS signs. We found that those patients who had severe symptoms of VD on the FS checklist recovered well. According to the theory proposed by Flammer, the higher the FS checklist value, the more likely will patients suffer from VD, which is one of the main causes of vision loss (the other being increased intraocular pressure). Indeed, glaucoma is known to be associated with hemodynamic changes and reduced blood flow regulation in the blood vessels [23, 63]. We have recently argued that better blood flow (autoregulation) leads to better recovery [22]. The reason is that different therapies can activate (improve) residual vision including vision restoration training, non-invasive brain stimulation, or blood flow–enhancing medications. Proposed mechanisms include the reorganization of brain functional networks and improved vascular regulation, both of which support recovery and restoration. Considering that ACS enhances blood flow, our observation of greater recovery in patients with FS signs supports the proposal that patients affected by VD also benefit more from blood flow–enhancing ACS.

We have recently suggested that a major cause of the FS is mental stress [36], which now raises the question how stress and vision restoration relate.

Chronic stress and vision recovery

It is known that severe chronic worrying and VD are related to stress [36], increasing the risk of coronary heart disease [64] and glaucoma, due to hemodynamic changes in the eye and other organs [23, 63]. Surprisingly, in the present study, we found no correlation between the level of chronic stress and the magnitude of vision recovery. Therefore, in our patient group, a direct link of Flammer signs, personality disposition, and mental stress could not be established. Several reasons might explain this missing correlation: (i) the sample size of our study was too small (ii) the TICS questionnaire is not sensitive enough or inappropriate because it contains many items related to the working age group to which only 40% of our patients belonged (iii) the retrospective study design with its inherent ambiguity regarding the cause-effect problem is insensitive to answering this question and (iv) persons unable to recognize their stress-associated feeling and actions (“I am not stressed at all”) might be more prone to psychosomatic reactions. This might lead to a mismatch between subjective perception of stress and how the body responds to stress.

Correlating individual items of the NEO-FFI and FS checklist with vision recovery

Because only the factors of neuroticism and conscientiousness correlated significantly with vision recovery, we next wished to explore the role of the other three personality traits as well (agreeableness, openness, and extraversion). As shown in Table 5, a number of individual items from these domains correlated with vision recovery. The direction of most of the correlations was consistent with the hypothesis that stress personality is negatively correlated with recovery as confirmed by the chi-square tests.

Comparing vision recovery glaucoma and non-glaucoma patients

When dividing the results of our patients into two groups with or without glaucoma, we found that the correlation of personality traits and vision recovery was somewhat different. Whereas in glaucoma patients poor recovery was associated with neuroticism, lack of social recognition, and chronic worrying, in non-glaucoma patients poor recovery was also associated with chronic worrying and lack of social recognition. But these patients had greater openness, conscientiousness, social overload, pressure to perform, and FS signs.

Because the non-glaucoma group contains many different diseases, it is difficult to explain the exact influencing factor. Yet, even this subdivision of groups confirms that neuroticism, lack of social recognition, and chronic stress play a very important role.

While our retrospective study does not inform us about causality, we assume that personality traits are rather stable, i.e., patients’ personality is similar before therapy and several years after therapy. In the Yan study [65], the authors found that glaucoma patients had higher scores of neuroticism, and, with logistic regression analysis, Cheng [41] made similar observations that neuroticism was one of the significant predictors of self-reported eye condition. We therefore propose that neuroticism affects glaucoma patients not only before but also after the treatment.

Lack of social recognition and chronic worrying were two other factors that affected our results. The present study generally confirms our early literature review showing that mental stress affected vision loss, and the study also showed that mental stress affected vision recovery in the glaucoma [36].

We speculate the following: (personality-mediated) chronic stress and worrying are a major cause of vision loss. Possibly, by way of inducing VD in the eye and brain, such stress and worrying can inactivate neurons. Therefore, patients with VD benefit most from the blood flow–enhancing ACS therapy.

Other sources of variability

There are also other sources of variability. One source is age, which correlates with the reduction of the visual fields [66] and also correlates with improvement by using vision restoration therapy (VRT). For example, a large clinical observational study showed that VRT improved vision by 17.2% and those over the age of 65 benefited most [10].

There are also gender differences in blindness around the world about two-thirds of those affected are female, and the most impoverished women are particularly vulnerable to life-threatening limitations due to visual impairment [67]. Also, of all people affected by FS, about 70% are women, who have a greater tendency to suppress anger because of stereotypic feminine gender socialization. This phenomenon was attributed to the traditional women’s role found in such patients [68].

Is there a correlation or cause-effect relationship between attractiveness and feet? - Psychology

Multiple Choice
Identify the choice that best completes the statement or answers the question.

The hindsight bias refers to people's tendency to

dismiss the value of replication.

reject any ideas that cannot be scientifically tested.

exaggerate their ability to have foreseen the outcome of past events.

assume that correlation proves causation.

overestimate the extent to which others share their opinions.

Giving half the members of a group some purported psychological finding and the other half an opposite result is an easy way to demonstrate the impact of

the double-blind procedure.

Professor Smith told one class that alcohol consumption has been found to increase sexual desire. He informed another class that alcohol consumption has been found to reduce sexual appetite. The fact that neither class was surprised by the information they received best illustrates the power of

the double-blind procedure.

The hindsight bias leads people to perceive research findings as

Alexandra is told that research supports the value of cosmetic surgery for boosting self-esteem. Belinda is told that the esteem-enhancing value of cosmetic surgery has been refuted by research. Both women would consider the findings to be common sense. This best illustrates the power of

the double-blind procedure.

According to Emily's grandfather, Adolf Hitler's obvious emotional instability made it clear from the beginning days of his international conflicts that Germany would inevitably lose World War II. The grandfather's claim best illustrates

Formulating testable hypotheses before conducting research is most directly useful for restraining a thinking error known as

The scientific attitude of humility is most likely to be undermined by

When we see certain outcomes as obvious based on what has occurred, we may be experiencing

Our tendency to believe we know more than we do illustrates

When provided with the unscrambled solution to anagrams, people underestimate the DIF of solving the anagrams by themselves. This best illustrates

Thinking that she had outperformed most of her classmates, Glenda was surprised to receive just an average grade on her psychology test. Glenda's experience best illustrates

Which of the following is most likely to inhibit critical thinking?

the double-blind procedure

Megan was certain that she would never live far away from her family. However, in order to further her career, she decided to move. Megan's experience best illustrates

Political officials who have no doubt that their own economic and military predictions will come true most clearly demonstrate

Sasha believes that she is a very good driver. Her belief leads her to take unnecessary risks, such as driving too fast and cutting in front of other drivers. Sasha's driving appears to be affected by

Basing decisions or conclusions on observable evidence describes which of the following?

Which of the following questions most likely could be answered using an empirical approach?

Is human nature basically good or evil?

What happens after we die?

How will style choices change in the future?

What is the basis of faith?

What is the advantage of researchers using an empirical approach in evaluating the accuracy of eyewitness testimony?

Researchers would experience greater overconfidence in their findings.

Such an approach allows researchers to set aside their critical thinking and explore their intuition.

Under controlled conditions, researchers collect evidence that may justify a cause-effect conclusion.

The empirical approach fosters conditions necessary for hindsight bias to occur.

Researchers may greatly overestimate eyewitness recollections when using the empirical approach.

Dr. Donelian wants to reduce his students' perception that psychological experiments merely document the obvious. His best strategy would be to ask the students to

describe how experimental hypotheses were derived from basic psychological principles.

predict the outcomes of experiments before they are told the actual results.

explain the outcomes of experiments after they are told the actual results.

personally engage in naturalistic observation.

survey students living on campus

Historians of science describe which three attitudes as the basis of the scientific viewpoint?

intelligence, dedication, thoroughness

morality, detail-orientation, cynicism

achievement-oriented, intellectual, empirical

curiosity, skepticism, humility

atheism, humanism, cognition

Which two questions exemplify the scientific attitude?

What do you mean? How do you know?

Who believes you? What are their qualifications?

How common is this answer? How many people agree?

Is this an established truth? How long has it been considered fact?

Which truths does this agree with? Which truths does it contradict?

A questioning attitude regarding psychologists' assumptions and hidden values best illustrates

When you question whether anecdotal evidence can be generalized to all people, you are applying

Critical thinkers can best be described as

To examine assumptions, discern hidden values, evaluate evidence, and assess conclusions is to engage in

creating operational definitions.

Examining correlational evidence to determine what further research would be needed to establish a causal relationship is an example of ________ thinking?

The news media reported that a new pesticide was not harmful to humans. Which of the following statements best exemplifies critical thinking in response to this report?

“I think I will try this pesticide on my own garden to kill pests.”

“I don't like to use pesticides, but this one is safe. ”

“I think I'll use this product, but I think I'll wear gloves.”

“I wonder who funded this study?”

“I don't believe this study because I got a rash after using this poison on my garden.”

According to Professor Fayad, we like people who like us because their affection for us boosts our own self-esteem. His idea is an example of

What do scientists call an explanation that organizes observations and predicts future behaviors or events?

Professor Shalet contends that parents and children have similar levels of intelligence largely because they share common genes. His idea is best described as a(n)

observable relationship between specific independent and dependent variables.

testable prediction that gives direction to research.

set of principles that organizes observations and explains newly discovered facts.

unprovable assumption about the unobservable processes that underlie psychological functioning.

statement of procedures used to define research variables.

Hypotheses are best described as

Professor Delano suggests that because people are especially attracted to those who are good-looking, handsome men will be more successful than average-looking men in getting a job. The professor's prediction regarding employment success is an example of

an operational definition.

Dr. Roberts hypothesized that students in a classroom seating 30 would get higher course grades than students seated in an auditorium seating 300. In this example,

Dr. Roberts has found a cause-effect relationship.

Dr. Roberts has found a positive correlation between classroom size and course grades.

the independent variable is the measurement of course grades.

classroom size has been operationally defined.

Dr. Roberts has demonstrated the importance of random sampling.

A specification of how a researcher measures a research variable is known as a(n)

An experiment was designed to study the potential impact of alcohol consumption on emotional stability. A specification of the procedures used to measure emotional stability illustrates

an operational definition.

the double-blind procedure.

The process of replication is most likely to be facilitated by

the selection of random samples.

perceiving order in random events.

repeating an earlier research study.

rejecting ideas that cannot be scientifically tested.

overestimating the extent to which others share our views.

Which technique involves repeating the essence of an earlier research study with different participants and in different circumstances?

the double-blind procedure

The explanatory power of a scientific theory is most closely linked to its capacity to generate testable

Professor Ambra was skeptical about the accuracy of recently reported research on sleep deprivation. Which process would best enable her to assess the reliability of these findings?

Why is replication important to science?

It allows you to obtain a representative sample of cases to study.

The natural setting eliminates the artificial environment of a lab.

Repeated research with similar results increases confidence in the reliability of the original findings.

Researchers can test the impact of belief on behavior.

Minimizing preexisting differences between groups increases confidence in the findings.

To understand the unusual behavior of an adult client, a clinical psychologist carefully investigates the client's current life situation and his physical, social-cultural, and educational history. Which research method has the psychologist used?

Which research method is typically used to examine one participant in depth, usually because the individual's situation/behavior is rare or unusual?

Which of the following researchers used the case study method, carefully observing one exceptional individual in depth to reach conclusions that might be true of all of us?

In 1953, H.M. underwent surgery to control his seizures. Doctors removed tissue from the hippocampus. As a result H.M.'s memory was severely impaired. Psychologists studied H.M.'s memory function until his death in 2008. Which research method did the psychologists utilize in this situation?

In 1848, Phineas Gage, a railroad construction foreman, survived when an explosion drove an iron rod through his head damaging the functioning of the frontal lobes. This instance provided evidence that the frontal lobe plays a role in personality and behavior. Researchers have continued to study Gage's brain to better understand this link. Which research method is being used?

The biggest danger of relying on case-study evidence is that it

is based on naturalistic observation.

may be unrepresentative of what is generally true.

overestimates the importance of operational definitions.

leads us to underestimate the causal relationships between events.

relies mostly on correlational rather than causational evidence.

In which research method do we study one exceptional individual in depth and try to carefully draw conclusions about others based on the evidence?

What is the primary limitation of the case study research method?

It is not an empirical method.

The case study is not part of the scientific method.

Random sampling must be used to ensure representative findings.

Individual cases can be misleading and result in false generalizations.

Correlational findings from case studies cannot be interpreted as causal.

A researcher interested in investigating the attitudes or opinions of a large sample of people is most likely to use which research method?

A majority of respondents in a national survey agreed that “classroom prayer should not be allowed in public schools.” Only 33 percent of respondents in a similar survey agreed that “classroom prayer in public schools should be banned. ” These divergent findings best illustrate the importance of

Surveys indicate that people are much less likely to support “welfare” than “aid to the needy.” These somewhat paradoxical survey results best illustrate the importance of

Which research method would be most appropriate for investigating the relationship between the religious beliefs of Americans and their attitudes toward abortion?

The complete set of cases from which samples may be drawn is called a(n)

In order to learn about the political attitudes of all students enrolled at Arizona State University, Professor Marlow randomly selected 800 of these students to complete a questionnaire. In this instance, all the students enrolled at Arizona State University are considered to be a(n)

Which procedure helps to ensure that the participants in a survey are representative of a larger population?

To learn about the TV viewing habits of all the children attending Oakbridge School, Professor DeVries randomly selected and interviewed 50 of the school's students. In this instance, all the children attending the school are considered to be a(n)

To assess reactions to a proposed tuition hike at her college, Ariana sent a questionnaire to every fifteenth person in the college registrar's alphabetical listing of all currently enrolled students. Ariana employed the technique of

After noting that a majority of professional basketball players are African-American, Ervin concluded that African-Americans are better athletes than members of other racial groups. Ervin's conclusion best illustrates the danger of

generalizing from vivid cases.

randomly assigning variables.

Which of the following is most useful for helping survey researchers avoid false generalizations?

Psychologists who carefully watch the behavior of chimpanzee societies in the jungle are using a research method known as

To describe the behavior of animals in their native habitats, researchers are most likely to make use of

the double-blind procedure.

To study the development of relationships, Dr. Rajiv carefully observed and recorded patterns of verbal and nonverbal behaviors among boys and girls in the school yard. Which research method did Dr. Rajiv employ?

Professor Ober carefully observes and records the behaviors of children in their classrooms in order to track the development of their social and intellectual skills. Professor Ober is most clearly engaged in

To compare the pace of life in different countries, investigators measured the speed with which postal clerks completed a simple request. This best illustrates the use of a research method known as

the double-blind procedure.

Correlational research is most useful for purposes of

A correlation coefficient is a measure of the

difference between the highest and lowest scores in a distribution.

average squared deviation of scores from a sample mean.

direction and strength of the relationship between two variables.

statistical significance of a difference between two sample means.

frequency of scores at each level of some measure.

Which of the following statistical measures is most helpful for indicating the extent to which high school grades predict college grades?

To graphically represent the correlation between two variables, researchers often construct a

If psychologists discovered that wealthy people are less satisfied with their marriages than poor people are, this would indicate that wealth and marital satisfaction are

If college graduates typically earn more money than high school graduates, this would indicate that level of education and income are

If the correlation between the physical weight and reading ability of children is +0.85, this would indicate that

there is very little statistical relationship between weight and reading ability among children.

low body weight has a negative effect on the reading abilities of children.

better reading ability is associated with greater physical weight among children.

body weight has no causal influence on the reading abilities of children.

weight is a causal variable dependent on reading ability.

Which of the following correlations between self-esteem and body weight would enable you to most accurately predict body weight from knowledge of level of self-esteem?

Which of the following correlation coefficients expresses the weakest degree of relationship between two variables?

Which of the following correlations between annual income and education level would best enable you to predict annual income on the basis of level of education?

Which of the following correlation coefficients expresses the strongest degree of relationship between two variables?

To determine whether the strength of people's self-esteem is related to their income levels, researchers would most likely make use of

To discover the extent to which economic status can be used to predict political preferences, researchers are most likely to use

Based on the information provided in the chart above, which scatterplot best represents the relationship between study hours and test grades. (In the scatterplots below, the x-axis is hours of study and the y-axis is test grades.)

A moderate positive correlation has been found between a person's weight and hours of television watched per week. Which of the following scatterplots best shows this relationship?

( Drawings 1-4 taken from www.stat.auckland. ac. nz/

Which of the following scatterplots represents the weakest relationship?

( Drawings 1-4 taken from www.stat.auckland. ac. nz/

Which of the following scatterplots represents the strongest relationship?
( Drawings 1-4 taken from www.stat.auckland. ac. nz/

An extensive survey revealed that children with relatively high self-esteem tend to picture God as kind and loving, whereas those with lower self-esteem tend to perceive God as angry. The researchers concluded that the children's self-esteem had apparently influenced their views of God. This conclusion best illustrates the danger of

perceiving order in random events.

generalizing from extreme examples.

randomly sampling children's views.

exaggerating the extent to which others share our beliefs.

assuming that correlation proves causation.

Following the scientific discovery that a specific brain structure is significantly larger in violent individuals than in those who are nonviolent, a news headline announced: “Enlarged Brain Structure Triggers Violent Acts.” The headline writer should most clearly be warned about the dangers of

perceiving illusory correlations.

explaining events in hindsight.

confusing correlation with causation.

generalizing from unrepresentative samples.

discerning order in random events.

If psychologists discovered that more intelligent parents have smarter children than less intelligent parents, this would demonstrate that

intelligence is inherited.

more intelligent parents provide their children with greater educational opportunities than do less intelligent parents.

the intelligence of parents and children is positively correlated.

experiments based on this relationship would indicate causation.

intelligence of children and parents are negatively correlated.

Which of the following statements is most correct about the relationship between correlation and causation?

Correlations are statistical relationships, causations are logical relationships.

Correlation indicates the possibility of a causal relationship, but it does not prove causation.

If one variable is strongly positively correlated with another variable, the relationship is causal.

if one variable is strongly negatively correlated with another variable, the relationship is not causal.

Both correlations and causations need to be proven with experimental data.

Which of the following is the best definition of illusory correlation?

a statistical relationship between two variables

a perceived but nonexistent correlation

any independent variable that does not truly cause a dependent variable

a scatterplot indicating the likelihood that a variable will or will not change

a predication about the relationship between two variables

The belief that weather conditions signal the onset of arthritis pain best illustrates

The sequential occurrence of two highly unusual events is most likely to contribute to

Because she had a serious traffic accident on Friday the 13th of last month, Felicia is convinced that all Friday the 13ths will bring bad luck. Felicia's belief best illustrates

Redelmeier and Tversky (1996) followed 18 patients with arthritis for 18 months. Patients were asked to record their pain and joint tenderness, while researchers documented changes in the weather. Nearly all patients believed that their condition was associated with weather changes, when the actual correlation was near zero. These participants need to be reminded that

the results may not be statistically significant.

we are likely to recall instances that confirm our beliefs.

the sample size may not have been representative of the population.

the results of correlational studies are typically highly questionable.

subtle changes in how questions are worded can have major effects on results.

The King James Version of the Bible was completed when William Shakespeare was 46 years old. In Psalm 46 of this translation, the forty-sixth word is “shake,” and the forty-sixth word from the end is “spear.” Before concluding that the biblical translators were trying to be humorous with these specific word placements, you would be best advised to recognize the danger of

considering these facts as statistically significant.

randomly sampling biblical passages.

generalizing from extreme examples.

assuming that most people share your opinions.

perceiving order in coincidental events.

A researcher interested in proving a causal relationship between two variables should choose which research method?

In a test of the effects of sleep deprivation on problem-solving skills, research participants are allowed to sleep either 4 or 8 hours on each of three consecutive nights. This research is an example of

A research method in which an investigator manipulates factors that potentially produce a particular behavior is called a(n)

To exercise maximum control over the factors they are interested in studying, researchers engage in

The most foolproof way of testing the true effectiveness of a newly introduced method of psychological therapy is by means of

Researchers are interested in studying the relationship between poor prenatal nutrition and early cognitive development. Because of ethical concerns, which research method would be most appropriate for researchers to use?

Researchers are interested in studying the impact of drugs on human fetuses. In this case, why would a correlational study be more appropriate than an experiment?

because cause and effect can only be determined by a correlational study

because correlational studies allow you to observe behavior in nonartificial environments

because researchers using correlational studies may generalize to the population from an atypical case

because participants could not be ethically assigned to an experimental or control condition

because correlational studies permit researchers to estimate the reported behaviors of a whole population

Researchers use experiments rather than other research methods in order to distinguish between

random samples and representative samples.

hypotheses and operational definitions.

To accurately infer cause and effect, experimenters should use

To assess the effect of televised violence on aggression, researchers plan to expose one group of children to violent movie scenes and another group to nonviolent scenes. To reduce the chance that the children in one group have more aggressive personalities than those in the other group, the researchers should make use of

the double-blind procedure.

To study the effects of noise on worker productivity, researchers have one group of subjects work in a noisy room and a second group work in a quiet room. To ensure that any differences in the productivity of the two groups actually result from the different noise levels to which the groups are exposed, the researchers would use

Both the researchers and the participants in a memory study are ignorant about which participants have actually received a potentially memory-enhancing drug and which have received a placebo. This investigation involves the use of

the double-blind procedure.

To minimize the extent to which outcome differences between experimental and control conditions can be attributed to placebo effects, researchers make use of

the double-blind procedure.

Abdul has volunteered to participate in an experiment evaluating the effectiveness of aspirin. Neither he nor the experimenters know whether the pills he takes during the experiment contain aspirin or are merely placebos. The investigators are apparently making use of

the double-blind procedure.

the overconfidence effect.

In a study of the effects of alcohol consumption, some participants drank a nonalcoholic beverage that actually smelled and tasted like alcohol. This nonalcoholic drink was a

The relief of pain following the ingestion of an inert substance that is presumed to have medicinal benefits illustrates

In a drug treatment study, participants given a pill containing no actual drug are receiving a(n)

The healing power of positive expectations is best illustrated by

In an experiment designed to study the effectiveness of a new drug, research participants who receive a placebo are participating in the ________ condition.

To provide a baseline against which they can evaluate the effects of a specific treatment, experimenters make use of a(n)

Random sampling is to ________ as random assignment is to ________.

correlational studies case studies

illusory correlation control group

Which technique most clearly minimizes the likelihood that any outcome differences between the experimental and control conditions can be attributed to age or personality differences in research participants?

the double-blind procedure

Participants in an experiment are said to be blind if they are uninformed about

the experimental hypothesis being tested.

whether the experimental findings will be statistically significant.

how the dependent variable is measured.

which experimental treatment, if any, they are receiving.

what research method is being used.

Which of the following is true for those assigned to the experimental group in an experiment?

The experimenter exerts the greatest influence on participants' behavior.

The research participants are exposed to all the different hypotheses.

The experimental group receives the experimental treatment

The experimental group does not receive the experimental treatment

The operational definition is not applied to their variables.

Which of the following is true for those assigned to a control group?

The experimenter exerts the greatest influence on participants' behavior.

The research participants are exposed to all the different experimental treatments.

The research participants are exposed to the most favorable levels of experimental treatment.

The experimental treatment is absent.

The operational definition is not applied to their variables.

Knowing the difference between an experimental condition and a control condition is most relevant to understanding the nature of

In the hypothesis “Students who study a list of terms in the morning, just after waking up, will recall more terms than students who study the list just before falling asleep,” what is the independent variable?

number of terms remembered

In the hypothesis “Students who study a list of terms in the morning, just after waking up, will recall more terms than students who study the list just before falling asleep,” what is the dependent variable?

number of terms remembered

In an experiment, researchers manipulate one factor to see its effect on another factor, called the

What technique do researchers use to reduce the impact of confounding variables?

measures of central tendency

When you read a bar graph, it is most important for you to

understand the concept of the overconfidence effect.

mentally transform the data into a scatterplot.

identify the value of the standard deviation.

note the range and size of the scale values.

remember that correlation facilitates prediction.

Bar graphs allow researchers to

In a group of five individuals, two report annual incomes of $10,000, and the other three report incomes of $14,000, $15,000, and $31,000, respectively. The mode of this group's distribution of annual incomes is

Mr. and Mrs. Klostreich have six children aged 5, 6, 6, 7, 8, and 16. The mean age of the Klostreich children is

During the past year, Zara and Ivan each read 2 books, but George read 9, Ali read 12, and Marsha read 25. The median number of books read by these individuals was

Six different high school students spent $10, $13, $2, $12, $13, and $4, respectively, on entertainment. The mode of this group's entertainment expenditures is

The arithmetic average of a distribution of scores is the

The most commonly reported measure of central tendency is the

During the past month, Henri and Sylvia each ate 10 candy bars, while Jerry ate 8, Tricia ate 6, and Tahli ate only 1. The mean number of candy bars eaten by these individuals was

Mr. and Mrs. Berry have five children aged 2, 3, 7, 9, and 9. The median age of the Berry children is

In a distribution of test scores, which measure of central tendency would likely be the most affected by a couple of extremely high scores?

When Mr. Adams calculated his students' algebra test scores, he noticed that two students had extremely low scores. Which measure of central tendency is affected most by the scores of these two students?

Seven members of a boys' club reported the following individual earnings from their sale of cookies: $2, $9, $8, $10, $4, $9, and $7. In this distribution of individual earnings

the median is greater than the mean and greater than the mode.

the median is less than the mean and less than the mode.

the median is greater than the mean and less than the mode.

the median is less than the mean and greater than the mode.

the median is equal to the mean and equal to the mode.

Seven members of a Girl Scout troop report the following individual earnings from their sale of candy: $4, $1, $7, $6, $8, $2, and $7. In this distribution of individual earnings

the mean is equal to the mode and equal to the median.

the mean is less than the mode and equal to the median.

the mean is equal to the mode and greater than the median.

the mean is greater than the mode and greater than the median.

the mean is less than the mode and less than the median.

To understand the British newspaper headline “Income for 62% Is Below Average,” it is necessary to appreciate the distinction between the ________ and the mean.

For which of the following distributions of scores would the median most clearly be a more appropriate measure of central tendency than the mean?

For which of the following distributions of scores would the median most clearly be a more appropriate measure of central tendency than the mean?

Which measure of central tendency would be most appropriate in determining housing values in a particular community?

Why would the median, rather than the mean, be the appropriate measure of central tendency in determining housing values in a particular community?

The median is useful for measuring how much values deviate from one another.

The median is minimally affected by extreme scores.

The median is best used to sort values into groups.

The median allows you to examine the gap between the lowest and highest value.

The median allows you to generalize from representative samples to the general population.

Which measure of central tendency would a baseball manager be most likely to rely on in picking a pinch hitter in a tie game?

Variation is to central tendency as ________ is to ________.

The difference between the highest and lowest scores in a distribution is the

a total population from which samples may be drawn.

the difference between the highest and lowest scores in a distribution.

the most commonly used measure of variation.

the average deviation of scores from the mean.

the most frequently occurring score in a distribution of scores.

The IQ scores of the five members of the Duluth family are 100, 82, 104, 96, and 118. For this distribution of scores, the range is

During the last Central High School basketball game, the starting five players scored 11, 7, 21, 14, and 7 points, respectively. For this distribution of scores, the range is

Which of the following is a measure of the degree of variation among a set of events?

Evelyn wants to know how consistent her bowling scores have been during the past season. Which of the following measures would be most relevant to this specific concern?

Professor Woo noticed that the distribution of students' scores on her last biology test had an extremely small standard deviation. This indicates that the

test was given to a very small class of students.

students' scores tended to be very similar to one another.

mean test score was lower than the median score.

students generally performed very well on the test.

test was a poor measure of the students' knowledge.

On a 10-item test, three students in Professor Hsin's advanced chemistry seminar received scores of 2, 5, and 8, respectively. For this distribution of test scores, the standard deviation is equal to the square root of

Which measure of variation is most affected by extreme scores?

If scores on the Wechsler Adult Intelligence Scale (WAIS) are normally distributed, with a mean of 100 and a standard deviation of 15, what percentage of scores will fall between 85 and 115?

The distributions of which of the following MSCs of data are most likely to form a normal curve?

scores on a homework assignment

years of historical events

Coach Vroman attended a clinic to improve his basketball coaching skills. Afterward, he randomly assigned his seventh-grade players to two groups: Group 1 will be coached by the new method and Group 2 will be coached by his old method. He then measured their performance at one team practice to judge the effectiveness of the new coaching method. Which of the following might affect the statistical significance of his study?

Approval from an Institutional Review Board (IRb. was not obtained before beginning his study.

To determine the effectiveness of the new method, Coach Vroman must first find the median score of each group.

By testing only two groups, Coach Vroman's sample size may be too small and unrepresentative.

Coach Vroman should wait until next year to test the incoming freshman because his sample was biased.

A third variable, such as height, might affect the relationship between the two variables.

Dr. DeVries is interested in measuring how practice in problem solving affects this ability. The population of interest is high school seniors, and the sample consists of students who attend an exclusive college preparatory school. Half of the sample receives practice in solving particular MSCs of problems, while the other half does not. Both groups take the same problem-solving test. Which of the following might best explain why Dr. DeVries may not be able to generalize his findings?

He is not taking into account how the scores on the test might deviate from one another.

His data may be positively skewed.

He should have conducted his experiment in a lab instead of a natural setting.

His sample is not representative of the population.

He did not receive approval from an Institutional Review Board (IRb. before beginning his research.

Why are researchers careful to use large, representative samples in their studies?

The general public perceives these kinds of samples to be more scientific.

Policymakers demand larger, more representative sample sizes for political reasons.

Statistical methods only work for larger sample sizes.

It is more profitable to work with larger samples.

Larger, representative sample sizes help ensure reliable and valid results.

To determine whether a research finding is statistically significant, researchers