Deck 7: Bivariate Correlational Research

Question 1

When examining an association claim using a bar graph,an association is indicated by which of the following?

A) A difference in the height between the bars
B) The number of bars in the graph
C) The number of observations that make each bar
D) The direction of the bars
E) None of the above

Answer 1

A difference in the height between the bars

Question 2

RESEARCH STUDY 7.1
Dr. Oswald conducts a study examining the relationship between the number of friends one has and the experience of daily stress and life satisfaction. She randomly samples 1,500 elderly men and women in the Memphis, Tennessee, area in the southern United States. Below are her findings.
 Life satisfaction and experience of daily stress: r = -.57 (p = .01)
 Number of friends one has and experience of daily stress: r = .09, not sig.
 Number of friends one has and life satisfaction: r = .36 (p = .04)
Refer to Research Study 7.1 above to answer the following question. Dr.Oswald creates a scatterplot of the relationship between the experience of daily stress and life satisfaction.In doing so,she realizes there are three scores that seem to be very extreme and are nowhere near the other points on the scatterplot.Specifically,it appears that three people report very high levels of daily stress and very low levels of life satisfaction.Which of the following statements is true?

A) These scores may have strengthened the correlation between these two variables.
B) These scores are more likely to have an effect because of the large sample size.
C) These scores are more likely to have an effect because they are extreme on both variables.
D) Both a and c are true.
E) All of the above are true.

Answer 2

Both a and c are true.

Question 3

Which of the following graph formats is the best way to examine an association claim between a categorical variable and a quantitative variable?

A) A scatterplot
B) A line graph
C) A bar graph
D) A pie chart
E) All of the above

Answer 3

A bar graph

Question 4

RESEARCH STUDY 7.1
Dr. Oswald conducts a study examining the relationship between the number of friends one has and the experience of daily stress and life satisfaction. She randomly samples 1,500 elderly men and women in the Memphis, Tennessee, area in the southern United States. Below are her findings.
 Life satisfaction and experience of daily stress: r = -.57 (p = .01)
 Number of friends one has and experience of daily stress: r = .09, not sig.
 Number of friends one has and life satisfaction: r = .36 (p = .04)
Refer to Research Study 7.1 above to answer the following question. According to the benchmarks established by Cohen,what type of effect size has Dr.Oswald found for the association between number of friends people have and life satisfaction?

A) Very small
B) Small
C) Medium
D) Large
E) Very large

Question 5

RESEARCH STUDY 7.1
Dr. Oswald conducts a study examining the relationship between the number of friends one has and the experience of daily stress and life satisfaction. She randomly samples 1,500 elderly men and women in the Memphis, Tennessee, area in the southern United States. Below are her findings.
 Life satisfaction and experience of daily stress: r = -.57 (p = .01)
 Number of friends one has and experience of daily stress: r = .09, not sig.
 Number of friends one has and life satisfaction: r = .36 (p = .04)
Refer to Research Study 7.1 above to answer the following question. Dr.Oswald realizes that the women in her study have more friends than the men in her study.This might result in which of the following?

A) Outliers due to subgroups
B) Larger effect sizes
C) More measured variables
D) Spurious associations due to subgroups
E) None of the above

Question 6

RESEARCH STUDY 7.1
Dr. Oswald conducts a study examining the relationship between the number of friends one has and the experience of daily stress and life satisfaction. She randomly samples 1,500 elderly men and women in the Memphis, Tennessee, area in the southern United States. Below are her findings.
 Life satisfaction and experience of daily stress: r = -.57 (p = .01)
 Number of friends one has and experience of daily stress: r = .09, not sig.
 Number of friends one has and life satisfaction: r = .36 (p = .04)
Refer to Research Study 7.1 above to answer the following question. In determining whether the relationship between two of her variables was statistically significant,which of the following must be considered?

A) Sample size and number of variables analyzed
B) Direction of the association and strength of the association
C) Sample size and effect size
D) The number of outliers and the direction of the association
E) None of the above

Question 7

RESEARCH STUDY 7.1
Dr. Oswald conducts a study examining the relationship between the number of friends one has and the experience of daily stress and life satisfaction. She randomly samples 1,500 elderly men and women in the Memphis, Tennessee, area in the southern United States. Below are her findings.
 Life satisfaction and experience of daily stress: r = -.57 (p = .01)
 Number of friends one has and experience of daily stress: r = .09, not sig.
 Number of friends one has and life satisfaction: r = .36 (p = .04)
Refer to Research Study 7.1 above to answer the following question. Considering Dr.Oswald's sample,which of the following statements is true?

A) The association found in her study could probably generalize to teenagers.
B) The association found in her study could probably generalize to people in other large cities in Tennessee.
C) The association found in her study could probably generalize to people in New York City.
D) The association found in her study could probably generalize to elderly persons living in nursing homes.
E) All of the above are true.

Question 8

Which of the following tells you that an association claim is being made?

A) The graph used to interpret the results
B) The fact that the two variables are measured
C) The statistic used to interpret the results
D) The validities that can be established
E) None of the above

Question 9

RESEARCH STUDY 7.1
Dr. Oswald conducts a study examining the relationship between the number of friends one has and the experience of daily stress and life satisfaction. She randomly samples 1,500 elderly men and women in the Memphis, Tennessee, area in the southern United States. Below are her findings.
 Life satisfaction and experience of daily stress: r = -.57 (p = .01)
 Number of friends one has and experience of daily stress: r = .09, not sig.
 Number of friends one has and life satisfaction: r = .36 (p = .04)
Refer to Research Study 7.1 above to answer the following question. Dr.Oswald has decided to examine one of her relationships with a scatterplot to double-check for a curvilinear relationship.Which relationship will be most important for her to examine?

A) Life satisfaction and experience of daily stress
B) Number of friends one has and experience of daily stress
C) Number of friends one has and life satisfaction
D) Both a and b
E) Both a and c

Question 10

RESEARCH STUDY 7.1
Dr. Oswald conducts a study examining the relationship between the number of friends one has and the experience of daily stress and life satisfaction. She randomly samples 1,500 elderly men and women in the Memphis, Tennessee, area in the southern United States. Below are her findings.
 Life satisfaction and experience of daily stress: r = -.57 (p = .01)
 Number of friends one has and experience of daily stress: r = .09, not sig.
 Number of friends one has and life satisfaction: r = .36 (p = .04)
Refer to Research Study 7.1 above to answer the following question. The "not sig." in Dr.Oswald's findings indicates all of the following EXCEPT:

A) It is likely that the association between number of friends one has and experience of daily stress is from a zero association population
B) Effect size could not be calculated
C) There is not a statistically significant association between the two variables
D) She cannot reliably predict the experience of daily stress from the number of friends one has
E) All of the above are true

Question 11

RESEARCH STUDY 7.1
Dr. Oswald conducts a study examining the relationship between the number of friends one has and the experience of daily stress and life satisfaction. She randomly samples 1,500 elderly men and women in the Memphis, Tennessee, area in the southern United States. Below are her findings.
 Life satisfaction and experience of daily stress: r = -.57 (p = .01)
 Number of friends one has and experience of daily stress: r = .09, not sig.
 Number of friends one has and life satisfaction: r = .36 (p = .04)
Refer to Research Study 7.1 above to answer the following question. Dr.Oswald submits her study for publication in a scientific journal.If one of the peer reviewers is concerned about the external validity of her study,which of the following is the most important aspect of Dr.Oswald's study to consider?

A) The random sampling technique used to recruit the participants
B) The 1,500 people in the sample
C) The use of three measured variables
D) The number of significant findings
E) All of the above

Question 12

RESEARCH STUDY 7.1
Dr. Oswald conducts a study examining the relationship between the number of friends one has and the experience of daily stress and life satisfaction. She randomly samples 1,500 elderly men and women in the Memphis, Tennessee, area in the southern United States. Below are her findings.
 Life satisfaction and experience of daily stress: r = -.57 (p = .01)
 Number of friends one has and experience of daily stress: r = .09, not sig.
 Number of friends one has and life satisfaction: r = .36 (p = .04)
Refer to Research Study 7.1 above to answer the following question. In evaluating Dr.Oswald's study,you question the construct validity of the study.Which of the following questions would you be asking?

A) How did Dr. Oswald recruit her participants?
B) Which statistic did Dr. Oswald compute?
C) How reliable is the measure of daily stress?
D) Does the number of friends cause people to experience less stress?
E) How long did the study take to conduct?

Question 13

RESEARCH STUDY 7.1
Dr. Oswald conducts a study examining the relationship between the number of friends one has and the experience of daily stress and life satisfaction. She randomly samples 1,500 elderly men and women in the Memphis, Tennessee, area in the southern United States. Below are her findings.
 Life satisfaction and experience of daily stress: r = -.57 (p = .01)
 Number of friends one has and experience of daily stress: r = .09, not sig.
 Number of friends one has and life satisfaction: r = .36 (p = .04)
Refer to Research Study 7.1 above to answer the following question. Dr.Oswald creates a scatterplot of the relationship between the experience of daily stress and life satisfaction.In doing so,she realizes there are three scores that seem to be very extreme and are nowhere near the other points on the scatterplot.Specifically,it appears that three people report very high levels of daily stress and very low levels of life satisfaction.Dr.Oswald should probably consider these scores _________________.

A) Random
B) Moderators
C) Outliers
D) Curvilinear scores
E) None of the above

Question 14

When examining an association in which one variable is categorical and one is quantitative,which of the following statistical tests is likely to be used?

A) A t test
B) A phi coefficient
C) Point-biserial correlation
D) Either a or c
E) All of the above

Question 15

A study finds a correlation coefficient of r = .22.According to Cohen's benchmarks,the magnitude of this effect is:

A) Negative
B) Large
C) Multiply determined
D) Categorical
E) None of the above

Question 16

RESEARCH STUDY 7.1
Dr. Oswald conducts a study examining the relationship between the number of friends one has and the experience of daily stress and life satisfaction. She randomly samples 1,500 elderly men and women in the Memphis, Tennessee, area in the southern United States. Below are her findings.
 Life satisfaction and experience of daily stress: r = -.57 (p = .01)
 Number of friends one has and experience of daily stress: r = .09, not sig.
 Number of friends one has and life satisfaction: r = .36 (p = .04)
Refer to Research Study 7.1 above to answer the following question. Matt,Dr.Oswald's research assistant,is discussing the findings of the study with some other students.He claims that the experience of more daily stress causes people to have lower life satisfaction.Which of the following keeps Matt from being correct?

A) The study did not establish the covariance of cause and effect
B) The study did not establish temporal precedence
C) The study did not establish internal validity
D) Both b and c
E) All of the above

Question 17

RESEARCH STUDY 7.1
Dr. Oswald conducts a study examining the relationship between the number of friends one has and the experience of daily stress and life satisfaction. She randomly samples 1,500 elderly men and women in the Memphis, Tennessee, area in the southern United States. Below are her findings.
 Life satisfaction and experience of daily stress: r = -.57 (p = .01)
 Number of friends one has and experience of daily stress: r = .09, not sig.
 Number of friends one has and life satisfaction: r = .36 (p = .04)
Refer to Research Study 7.1 above to answer the following question. Which of the following conclusions can Dr.Oswald draw about the number of friends one has and life satisfaction,based on her statistical analyses?

A) The probability of her sample coming from a zero association population is about 4%.
B) The probability of her sample coming from a zero association population is about 96%.
C) The relationship is not statistically significant.
D) The strong correlation means that the number of friends one has causes increases in life satisfaction.
E) None of the above

Question 18

RESEARCH STUDY 7.1
Dr. Oswald conducts a study examining the relationship between the number of friends one has and the experience of daily stress and life satisfaction. She randomly samples 1,500 elderly men and women in the Memphis, Tennessee, area in the southern United States. Below are her findings.
 Life satisfaction and experience of daily stress: r = -.57 (p = .01)
 Number of friends one has and experience of daily stress: r = .09, not sig.
 Number of friends one has and life satisfaction: r = .36 (p = .04)
Refer to Research Study 7.1 above to answer the following question. Comparing all three correlations,Dr.Oswald will be most able to accurately predict life satisfaction from the experience of daily stress because:

A) The relationship is negative
B) The relationship has the largest effect size
C) The relationship was reported first
D) The relationship was statistically significant
E) None of the above-this relationship will not lead to the most accurate predictions.

Question 19

RESEARCH STUDY 7.1
Dr. Oswald conducts a study examining the relationship between the number of friends one has and the experience of daily stress and life satisfaction. She randomly samples 1,500 elderly men and women in the Memphis, Tennessee, area in the southern United States. Below are her findings.
 Life satisfaction and experience of daily stress: r = -.57 (p = .01)
 Number of friends one has and experience of daily stress: r = .09, not sig.
 Number of friends one has and life satisfaction: r = .36 (p = .04)
Refer to Research Study 7.1 above to answer the following question. Dr.Oswald finds that the relationship between the number of friends one has and life satisfaction is stronger for men than for women.In this study,sex (male or female)is considered a/an:

A) Outlier
B) Cause
C) Moderator
D) Effect
E) Spurious variable

Question 20

RESEARCH STUDY 7.1
Dr. Oswald conducts a study examining the relationship between the number of friends one has and the experience of daily stress and life satisfaction. She randomly samples 1,500 elderly men and women in the Memphis, Tennessee, area in the southern United States. Below are her findings.
 Life satisfaction and experience of daily stress: r = -.57 (p = .01)
 Number of friends one has and experience of daily stress: r = .09, not sig.
 Number of friends one has and life satisfaction: r = .36 (p = .04)
Refer to Research Study 7.1 above to answer the following question. Considering Dr.Oswald's study,her results could most safely be generalized to which of the groups below?

A) People in the southern United States
B) Men
C) Elderly people
D) People with a high number of friends
E) People with high life satisfaction

Question 21

RESEARCH STUDY 7.2
Dr. Moynihan conducts a study examining the relationship between the number of panic attacks a person experienced in the past month, the number of nightmares experienced in the past month, and people's levels of neuroticism (a personality trait characterized by instability, anxiety, and worry). She collects a convenience sample of 50 community college students (25 males, 25 females). Below are her findings.
A - number of panic attacks in the past month and neuroticism: r = -.03, not sig.
B - number of panic attacks in the past month and number of nightmares in the past month: r = -.14 (p = .05)
C - number of nightmares in the past month and neuroticism: r = .48 (p = .003)
Refer to Research Study 7.2 above to answer the following question.
State two questions that you might ask if you were to interrogate the construct validity of Dr.Moynihan's study.

Question 22

RESEARCH STUDY 7.2
Dr. Moynihan conducts a study examining the relationship between the number of panic attacks a person experienced in the past month, the number of nightmares experienced in the past month, and people's levels of neuroticism (a personality trait characterized by instability, anxiety, and worry). She collects a convenience sample of 50 community college students (25 males, 25 females). Below are her findings.
A - number of panic attacks in the past month and neuroticism: r = -.03, not sig.
B - number of panic attacks in the past month and number of nightmares in the past month: r = -.14 (p = .05)
C - number of nightmares in the past month and neuroticism: r = .48 (p = .003)
Refer to Research Study 7.2 above to answer the following question.
Draw a scatterplot for the three associations found by Dr.Moynihan.

Question 23

When evaluating the external validity of an association claim,which of the following is the most important issue to consider?

A) The way the sample was selected from the population
B) The size of the sample
C) The number of subgroups
D) The presence of outliers
E) The size of the original population

Question 24

For a third variable to be plausible as the explanation in an established association,which of the following must also be true?

A) The third variable must be related to both of the measured variables in the original association.
B) The third variable must be measured on the same scale as the original measured variables.
C) The third variable must be a categorical variable.
D) The third variable must have a positive relationship with the two measured variables in the original association.
E) The third variable must be spurious.

Question 25

What is the relationship between moderators and external validity?

A) Moderators suggest that associations may be spurious.
B) Moderators suggest that associations may not generalize to all subgroups of people.
C) Moderators are necessary for external validity to be established.
D) Moderators suggest that an association between two variables will extend to another variable.
E) Moderators tell us nothing about external validity.

Question 26

All of the following are true of outliers EXCEPT:

A) They have the biggest effect when dealing with large sample sizes
B) They can affect the direction of an association
C) They can affect the strength of an association
D) They can weaken a relationship
E) They are especially problematic when there are outliers on both variables

Question 27

RESEARCH STUDY 7.1
Dr. Oswald conducts a study examining the relationship between the number of friends one has and the experience of daily stress and life satisfaction. She randomly samples 1,500 elderly men and women in the Memphis, Tennessee, area in the southern United States. Below are her findings.
 Life satisfaction and experience of daily stress: r = -.57 (p = .01)
 Number of friends one has and experience of daily stress: r = .09, not sig.
 Number of friends one has and life satisfaction: r = .36 (p = .04)
Refer to Research Study 7.1 above to answer the following question. Dr.Oswald finds that the relationship between the number of friends one has and life satisfaction is stronger for men than for women.Why might Dr.Oswald have looked for this difference?

A) To examine her study's external validity
B) To examine her study's internal validity
C) To determine whether the association was statistically significant
D) To determine whether the association was curvilinear
E) To determine whether the association was spurious

Question 28

Which of the following is true of the relationship between effect size and statistical significance?

A) Effect size alone is sufficient to indicate statistical significance.
B) Statistical significance alone is sufficient to indicate effect size.
C) An association's effect size has no effect on statistical significance.
D) Effect size and statistical significance are synonymous terms.
E) None of the above are true.

Question 29

Martin has found a correlation of r ? .18 between the two variables of caffeine consumption and frontal lobe activity.This correlation is more likely to be statistically significant if:

A) The study can be applied to the real world
B) Martin used a larger number of subjects
C) Martin measured frontal lobe activity extremely accurately
D) Martin's measure of caffeine consumption is categorical
E) Martin's study is based on a random sample

Question 30

Stronger effect sizes allow for which of the following?

A) Greater likelihood of finding a statistically significant relationship
B) Greater accuracy in predicting one variable as opposed to another
C) Greater likelihood of a finding being important in the real world
D) Both a and c
E) All of the above

Question 31

Which of the following is NOT a question you should ask about the statistical validity of an association claim?

A) What is the effect size?
B) Is the correlation statistically significant?
C) Are there subgroups?
D) Is random assignment affecting the findings?
E) Could outliers be affecting the relationship?

Question 32

RESEARCH STUDY 7.2
Dr. Moynihan conducts a study examining the relationship between the number of panic attacks a person experienced in the past month, the number of nightmares experienced in the past month, and people's levels of neuroticism (a personality trait characterized by instability, anxiety, and worry). She collects a convenience sample of 50 community college students (25 males, 25 females). Below are her findings.
A - number of panic attacks in the past month and neuroticism: r = -.03, not sig.
B - number of panic attacks in the past month and number of nightmares in the past month: r = -.14 (p = .05)
C - number of nightmares in the past month and neuroticism: r = .48 (p = .003)
Refer to Research Study 7.2 above to answer the following question.
Explain the three associations from Dr.Moynihan's study in terms of direction of each association,statistical significance,and effect size (using Cohen's benchmarks).

Question 33

RESEARCH STUDY 7.2
Dr. Moynihan conducts a study examining the relationship between the number of panic attacks a person experienced in the past month, the number of nightmares experienced in the past month, and people's levels of neuroticism (a personality trait characterized by instability, anxiety, and worry). She collects a convenience sample of 50 community college students (25 males, 25 females). Below are her findings.
A - number of panic attacks in the past month and neuroticism: r = -.03, not sig.
B - number of panic attacks in the past month and number of nightmares in the past month: r = -.14 (p = .05)
C - number of nightmares in the past month and neuroticism: r = .48 (p = .003)
Refer to Research Study 7.2 above to answer the following question.
Of the three findings in Dr.Moynihan's study,which associations are statistically significant? What does it mean that an association is statistically significant?

Question 34

Which of the following is true of statistical significance testing?

A) It is a process of inference.
B) It can lead to an incorrect conclusion about the population.
C) It is synonymous with measuring effect size.
D) Both a and b are true.
E) All of the above are true.

Question 35

If an association study did not select people for the study by using random sampling,which of the following statements is true?

A) The association should be rejected as inconclusive.
B) The variables should be measured more than once.
C) The effect size should be considered, but tests of statistical significance should not.
D) Moderators should be looked for.
E) None of the above statements are true.

Question 36

In which of the following cases might a small effect still be important?

A) When the sample is very large
B) When the study has life-or-death implications
C) When the finding is also statistically significant
D) When external validity is high
E) None of the above

Question 37

Statistical significance depends on which of the following?

A) Sample size and number of variables analyzed
B) Direction of the association and strength of the association
C) Sample size and effect size
D) Number of outliers and direction of the association
E) None of the above

Question 38

Why are curvilinear relationships hard to detect with correlation coefficients (r)?

A) Because curvilinear relationships require a large amount of scores
B) Because curvilinear relationships have small effect sizes
C) Because r looks for the best straight line to fit the data
D) Because r assumes a zero association
E) Because r assumes a negative relationship

Question 39

RESEARCH STUDY 7.2
Dr. Moynihan conducts a study examining the relationship between the number of panic attacks a person experienced in the past month, the number of nightmares experienced in the past month, and people's levels of neuroticism (a personality trait characterized by instability, anxiety, and worry). She collects a convenience sample of 50 community college students (25 males, 25 females). Below are her findings.
A - number of panic attacks in the past month and neuroticism: r = -.03, not sig.
B - number of panic attacks in the past month and number of nightmares in the past month: r = -.14 (p = .05)
C - number of nightmares in the past month and neuroticism: r = .48 (p = .003)
Refer to Research Study 7.2 above to answer the following question.
Of the three findings in Dr.Moynihan's study,which finding has the largest effect size? Name two things that having a large effect size means.

Question 40

Which of the following is true of moderators?

A) They help establish a cause and effect relationship.
B) They decrease effect size.
C) They can inform external validity.
D) They weaken statistical significance.
E) None of the above are true.

Question 41

RESEARCH STUDY 7.2
Dr. Moynihan conducts a study examining the relationship between the number of panic attacks a person experienced in the past month, the number of nightmares experienced in the past month, and people's levels of neuroticism (a personality trait characterized by instability, anxiety, and worry). She collects a convenience sample of 50 community college students (25 males, 25 females). Below are her findings.
A - number of panic attacks in the past month and neuroticism: r = -.03, not sig.
B - number of panic attacks in the past month and number of nightmares in the past month: r = -.14 (p = .05)
C - number of nightmares in the past month and neuroticism: r = .48 (p = .003)
Refer to Research Study 7.2 above to answer the following question.
What is an outlier? What aspect of Dr.Moynihan's study makes his findings especially susceptible to outliers? Why is this a problem?

Question 42

RESEARCH STUDY 7.2
Dr. Moynihan conducts a study examining the relationship between the number of panic attacks a person experienced in the past month, the number of nightmares experienced in the past month, and people's levels of neuroticism (a personality trait characterized by instability, anxiety, and worry). She collects a convenience sample of 50 community college students (25 males, 25 females). Below are her findings.
A - number of panic attacks in the past month and neuroticism: r = -.03, not sig.
B - number of panic attacks in the past month and number of nightmares in the past month: r = -.14 (p = .05)
C - number of nightmares in the past month and neuroticism: r = .48 (p = .003)
Refer to Research Study 7.2 above to answer the following question.
Examining Dr.Moynihan's study and using the three criteria of causation,why can he not say that the number of panic attacks in the past month causes one to have fewer nightmares in the same month?

Question 43

Draw a scatterplot for the following three associations:a.A curvilinear associationb.A positive association with a large effect sizec.A zero association

Question 44

RESEARCH STUDY 7.2
Dr. Moynihan conducts a study examining the relationship between the number of panic attacks a person experienced in the past month, the number of nightmares experienced in the past month, and people's levels of neuroticism (a personality trait characterized by instability, anxiety, and worry). She collects a convenience sample of 50 community college students (25 males, 25 females). Below are her findings.
A - number of panic attacks in the past month and neuroticism: r = -.03, not sig.
B - number of panic attacks in the past month and number of nightmares in the past month: r = -.14 (p = .05)
C - number of nightmares in the past month and neuroticism: r = .48 (p = .003)
Refer to Research Study 7.2 above to answer the following question.
Imagine that Dr.Moynihan is concerned about curvilinear relationships.Which of the three relationships is most likely to be affected by a curvilinear relationship? How should Dr.Moynihan check for this type of relationship? Why would this be effective?

Question 45

What does it mean that an association is "spurious"? What can cause spurious associations?

Question 46

RESEARCH STUDY 7.2
Dr. Moynihan conducts a study examining the relationship between the number of panic attacks a person experienced in the past month, the number of nightmares experienced in the past month, and people's levels of neuroticism (a personality trait characterized by instability, anxiety, and worry). She collects a convenience sample of 50 community college students (25 males, 25 females). Below are her findings.
A - number of panic attacks in the past month and neuroticism: r = -.03, not sig.
B - number of panic attacks in the past month and number of nightmares in the past month: r = -.14 (p = .05)
C - number of nightmares in the past month and neuroticism: r = .48 (p = .003)
Refer to Research Study 7.2 above to answer the following question.
Imagine that Dr.Moynihan finds two outliers.These two people report a very high number of nightmares in the past month and have very high scores on neuroticism.Why should Dr.Moynihan be worried about the presence of these two outliers?

Question 47

RESEARCH STUDY 7.2
Dr. Moynihan conducts a study examining the relationship between the number of panic attacks a person experienced in the past month, the number of nightmares experienced in the past month, and people's levels of neuroticism (a personality trait characterized by instability, anxiety, and worry). She collects a convenience sample of 50 community college students (25 males, 25 females). Below are her findings.
A - number of panic attacks in the past month and neuroticism: r = -.03, not sig.
B - number of panic attacks in the past month and number of nightmares in the past month: r = -.14 (p = .05)
C - number of nightmares in the past month and neuroticism: r = .48 (p = .003)
Refer to Research Study 7.2 above to answer the following question.
How strong is the external validity of Dr.Moynihan's study? How does the fact that he finds no differences in the associations in men and women also speak to the study's external validity?

Question 48

What are the five questions that consumers of research should ask to evaluate the statistical validity of an association claim?

Question 49

Why is the size of a sample not as important to external validity as the way a sample was collected?

Question 50

Name two ways in which the analysis of an association between two quantitative variables differs from the analysis of an association between a categorical variable and a quantitative variable.