# Quiz 10: The Paired-Samples T Test

Psychology

Q 1Q 1

A psychologist is interested in whether working memory is influenced by sleep loss.The psychologist administers a measure of working memory to a group of subjects at 8 a.m..on Day 1 of the study and then again at 8 a.m.on Day 2 of the study, after keeping the subjects awake the entire night.Does sleep loss affect working memory? What statistical analysis should be performed to answer this question?
A) single-sample t test
B) z test
C) standard deviation analysis
D) paired-samples t test

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Multiple Choice

D

Q 2Q 2

A study by Bettmann (2007) published in the Journal of the American Psychoanalytic Association assessed whether the attachment relationships between adolescents and their parents change as a result of a residential wilderness treatment experience for the adolescents.Participants completed the Adolescent Attachment Questionnaire at the start and at the end of the wilderness program.Which statistical test should be used to determine whether the wilderness treatment affected attachment relationships?
A) single-sample t test
B) z test
C) effect size test
D) paired-samples t test

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Multiple Choice

D

Q 3Q 3

In a within-groups design with two groups, the appropriate hypothesis test is a(n):
A) single-sample t test.
B) two-way analysis of variance.
C) paired-samples t test.
D) independent-samples t test.

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Multiple Choice

C

Q 4Q 4

Another name for a paired-samples t test is the _____ t test.
A) single-sample
B) dependent-samples
C) independent-samples
D) no-sample

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Multiple Choice

Q 5Q 5

The comparison distribution in a paired-samples t test is a distribution of:
A) mean difference scores.
B) differences between means.
C) means.
D) scores.

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Multiple Choice

Q 6Q 6

In a paired-samples t test, the comparison distribution is a distribution of:
A) mean difference scores.
B) raw score differences.
C) median distribution scores.
D) means.

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Multiple Choice

Q 7Q 7

When conducting a paired-samples t test, the sample mean difference is compared to:
A) a distribution of mean differences.
B) sample means.
C) differences between means.
D) the t distribution.

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Multiple Choice

Q 8Q 8

A clinical researcher was interested in determining whether her interventions were effective in minimizing depression symptoms among participants.To assess the effectiveness of the treatment program, she administered a depression inventory prior to treatment and after treatment.She hypothesized that depression scores would be lower at time two compared to time one.She then compared the mean differences between the two groups and found that the treatment was effective.The dependent variable in this study is:
A) depression scores.
B) gender.
C) age.
D) time.

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Multiple Choice

Q 9Q 9

A clinical researcher was interested in determining whether her interventions were effective in minimizing depression symptoms among participants.To assess the effectiveness of the treatment program, she administered a depression inventory prior to treatment and after treatment.She hypothesized that depression scores would be lower at time two compared to time one.She then compared the mean differences between the two groups and found that the treatment was effective.The independent variable in this study is:
A) depression scores.
B) gender.
C) age.
D) time.

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Multiple Choice

Q 10Q 10

According to the null hypothesis, the mean difference for the comparison distribution in a paired-samples t test is:
A) always 0.
B) sometimes 0.
C) always 1.
D) sometimes 1.

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Multiple Choice

Q 11Q 11

Twenty people participate in a weight-loss program for 2 months.Their weights after the 2 months are compared to their starting weights.What kind of mean difference might be expected if the null hypothesis is true for a paired-samples t test?
A) a loss of pounds, on average, showing the effectiveness of the program
B) a negative mean difference, indicating significant weight loss
C) no change in weight or weight gain, indicating that the program does not work
D) weight loss, indicating that the program does not work

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Multiple Choice

Q 12Q 12

Which of these is NOT an assumption of the paired-samples t test?
A) The dependent variable is a scale variable.
B) Participants are randomly selected.
C) There are fewer than 30 sample data.
D) The population is normally distributed.

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Multiple Choice

Q 13Q 13

A researcher studies 45 volunteer citizens from a small community and asks them about the amount of caffeine (in milligrams) they ingest before and after lunch each day, a phenomenon assumed to be normally distributed.Which assumption for the paired-samples t test is NOT met in this research design?
A) The dependent variable is a scale variable.
B) Participants are randomly selected.
C) The population is normally distributed.
D) All the assumptions are met.

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Multiple Choice

Q 14Q 14

A clinical researcher was interested in determining whether her interventions were effective in minimizing depression symptoms among participants.To assess the effectiveness of the treatment program, she administered a depression inventory prior to treatment and after treatment.She hypothesized that depression scores would be lower at time two compared to time one.She then compared the mean differences between the two groups and found that the treatment was effective.The researcher's hypothesis is:
A) one-tailed.
B) two-tailed.
C) not supported.
D) supported by null hypothesis.

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Multiple Choice

Q 15Q 15

The formula for the research hypothesis for a paired-samples t test is:
A) H

_{0}: _{1}= _{2.}B) H_{0}: _{1} _{2.}C) H_{1}: _{1}= _{2.}D) H_{1}: _{1} _{2.}Free

Multiple Choice

Q 16Q 16

The formula for the null hypothesis for a paired-samples t test is:
A) H

_{0}: _{1}= _{2.}B) H_{0}: _{1} _{2.}C) H_{1}: _{1}= _{2.}D) H_{1}: _{1} _{2.}Free

Multiple Choice

Q 17Q 17

A researcher studies 45 volunteer citizens from a small community and asks them about the amount of caffeine (in milligrams) they ingest before and after lunch each day.The null hypothesis for this paired-samples study could be:
A) more caffeine is ingested before lunch.
B) more caffeine is ingested after lunch.
C) there is a difference between the amount of caffeine ingested before and after lunch.
D) there is no difference between the amount of caffeine ingested before and after lunch.

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Multiple Choice

Q 18Q 18

Twenty college students experience the effects of alcohol on reaction time.They perform very basic timed responses in a driving simulator both before and after consuming several alcoholic beverages.The researcher collects a reaction-time result for each of the 20 students before and after intoxication, for a total of 40 measures.What is the null hypothesis for this paired-samples study?
A) There is no difference in reaction time before and after consuming alcohol.
B) Reaction time slows with alcohol consumption.
C) There is a difference in reaction time before and after consuming alcohol.
D) Reaction time quickens with alcohol consumption.

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Multiple Choice

Q 19Q 19

One of the first steps in calculating the dependent-samples t statistic is:
A) counterbalancing the order of the calculations.
B) finding the variance for each of the measured variables and then pooling them.
C) creating a difference score for each participant in the sample.
D) averaging the scores on each of the measured variables and finding the difference between those means.

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Multiple Choice

Q 20Q 20

What is the mean of the difference scores for the following difference scores: 2, 6.5, 3, 7.8, 10, 4.2?
A) 7.10
B) 5.58
C) 6.7
D) 33.5

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Multiple Choice

Q 21Q 21

For the following data, what is the mean of the difference scores?
A) 8.50
B) 5.00
C) 4.26
D) 11.33

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Multiple Choice

Q 22Q 22

What is the mean difference of the following difference scores: -1, -24, +20, -28, -4?
A) -6.40
B) -7.40
C) 6.17
D) 9.25

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Multiple Choice

Q 23Q 23

What is the standard error of the difference scores for a paired-samples t test for the following difference scores: 2, 6.5, 3, 7.8, 10, 4.2?
A) 46.69
B) 3.06
C) 1.25
D) 0.03

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Multiple Choice

Q 24Q 24

What is the paired-samples t test statistic for the following difference scores: 2, 6.5, 3, 7.8, 10, 4.2?
A) 7.10
B) 5.58
C) 4.46
D) 1.25

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Multiple Choice

Q 25Q 25

For the following data, what is the standard error of the difference scores?
A) 8.10
B) 4.26
C) 4.05
D) 2.10

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Multiple Choice

Q 26Q 26

What is the standard error for the paired-samples t test for the following difference scores: -1, -24, +20, -28, -4?
A) -0.92
B) -0.85
C) 6.96
D) 8.67

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Multiple Choice

Q 27Q 27

The critical cutoff(s) for a two-tailed, paired-samples t test with 24 participants at a p level of 0.05 is (are):
A) -2.074 and 2.074.
B) -2.069 or 2.069.
C) -1.714 and 1.714.
D) -1.711 or 1.711.

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Multiple Choice

Q 28Q 28

The critical cutoffs for a two-tailed, paired-samples t test with seven participants at a p level of 0.01 are:
A) -2.447 and 2.447.
B) -2.998 and 2.998.
C) -3.143 and 3.143.
D) -3.708 and 3.708.

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Multiple Choice

Q 29Q 29

The critical cutoff(s) for a one-tailed, paired-samples t test with 16 participants at a p level of 0.05 is (are):
A) -1.746 or 1.746.
B) -1.753 or 1.753.
C) -2.120 and 2.120.
D) -2.132 and 2.132.

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Multiple Choice

Q 30Q 30

The formula for the degrees of freedom for the paired-samples t test is:
A) N.
B) df

_{X}+ df_{Y.}C) N - 1. D) (N - 1)(N - 1).Free

Multiple Choice

Q 31Q 31

Twenty college students experience the effects of alcohol on reaction time.They perform very basic timed responses in a driving simulator both before and after consuming several alcoholic beverages.The researcher collects a reaction time result for each of the 20 students before and after intoxication, for a total of 40 measures.What are the degrees of freedom for this study?
A) 19
B) 20
C) 39
D) 40

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Multiple Choice

Q 32Q 32

For the following data, what is the paired-samples t test statistic?
A) 8.10
B) 4.05
C) 2.10
D) 1.17

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Multiple Choice

Q 33Q 33

What is the paired-samples t test statistic for the following difference scores: -1, -24, +20, -28, -4?
A) -0.92
B) -0.85
C) 6.96
D) 8.67

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Multiple Choice

Q 34Q 34

The denominator (bottom portion) of the ratio for calculating the paired-samples t statistic is the:
A) pooled variance.
B) estimated standard error of the distribution of mean difference scores.
C) estimated standard error of the sampling distribution of the mean.
D) estimated standard deviation.

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Multiple Choice

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Multiple Choice

Q 36Q 36

Assume the following for a paired-samples t test: N = 9, M

_{difference}= 13.19, s = 22.3.What is the t statistic? A) 0.59 B) 1.77 C) 4.40 D) 7.43Free

Multiple Choice

Q 37Q 37

Assume the following for a paired-samples t test: N = 12, M

_{difference}= 635.65, s = 608.50.What is the t statistic? A) 183.50 B) 52.97 C) 3.62 D) 1.04Free

Multiple Choice

Q 38Q 38

A paired-samples test is reported as t(18) = 1.73.What decision about this test should be made, assuming a two-tailed hypothesis test with a p level of 0.05?
A) fail to reject the research hypothesis
B) fail to reject the null hypothesis
C) reject the null hypothesis
D) reject the research hypothesis

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Multiple Choice

Q 39Q 39

What would be the decision for the following paired-samples t test: t(24) = 1.11, p > 0.05?
A) reject the null hypothesis
B) fail to reject the null hypothesis
C) reject the research hypothesis
D) fail to reject the research hypothesis

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Multiple Choice

Q 40Q 40

What would be the decision for the following paired-samples t test: t(24) = 4.11, p < 0.05?
A) reject the null hypothesis
B) fail to reject the null hypothesis
C) reject the research hypothesis
D) fail to reject the research hypothesis

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Multiple Choice

Q 41Q 41

What would be the decision for a two-tailed paired-samples t test where the t statistic is 4.67, with cutoffs of ±2.776?
A) reject the null hypothesis
B) fail to reject the null hypothesis
C) reject the research hypothesis
D) fail to reject the research hypothesis

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Multiple Choice

Q 42Q 42

What would be the decision for a two-tailed paired-samples t test where the t statistic is -4.67, with cutoffs of ±2.776?
A) reject the null hypothesis
B) fail to reject the null hypothesis
C) reject the research hypothesis
D) fail to reject the research hypothesis

Free

Multiple Choice

Q 43Q 43

What would be the decision for a two-tailed paired-samples t test where the t statistic is 2.67, with cutoffs of ±2.776?
A) reject the null hypothesis
B) fail to reject the null hypothesis
C) reject the research hypothesis
D) fail to reject the research hypothesis

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Multiple Choice

Q 44Q 44

What would be the decision for a two-tailed paired-samples t test where the t statistic is -2.67, with cutoffs of ±2.776?
A) reject the null hypothesis
B) fail to reject the null hypothesis
C) reject the research hypothesis
D) fail to reject the research hypothesis

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Multiple Choice

Q 45Q 45

The American Psychological Association encourages researchers to report _____ for paired-samples t tests.
A) effect sizes only
B) confidence intervals only
C) both effect sizes and confidence intervals
D) either effect sizes or confidence intervals

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Multiple Choice

Q 46Q 46

The final step in calculating a confidence interval for a paired-samples t test is to convert the:
A) effect sizes to t scores.
B) t statistics into raw mean differences.
C) t statistics into z statistics.
D) z statistics into t statistics.

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Multiple Choice

Q 47Q 47

When conducting a paired-samples t test, one can assess the research hypothesis and get a range of mean differences that could be expected in the future using:
A) a hypothesis test.
B) an effect size measure.
C) post-hoc tests.
D) a confidence interval.

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Multiple Choice

Q 48Q 48

Assume the following for a paired-samples t test: N = 19, M

_{difference}= 13.19, s = 22.3.What is the 95 percent confidence interval for a two-tailed test? A) [11.09, 15.29] B) [8.07, 18.31] C) [2.44, 23.94] D) [-10.76, 10.76]Free

Multiple Choice

Q 49Q 49

Assume the following for a paired-samples t test: N = 9, M

_{difference}= 101.4, s = 450.2.What is the 90 percent confidence interval for a two-tailed test? A) [-177.72, 380.52] B) [-101.4, 101.4] C) [-48.67, 251.47] D) [99.54, 103.26]Free

Multiple Choice

Q 50Q 50

What is the 95 percent confidence interval for a two-tailed test for the following difference scores: -1, -24, +20, -28, -4?
A) [-12.92, 25.71]
B) [-16.67, 31.47]
C) [-25.72, 12.92]
D) [-31.47, 16.67]

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Multiple Choice

Q 51Q 51

A researcher investigates whether chocolate affects mood.She recruits college students to take a mood inventory, ingest a quarter pound of chocolate, and then complete the mood inventory again.Given the confidence interval [2.34, 5.41], what decision about the hypothesis should be made?
A) Reject the null hypothesis and conclude that chocolate affected mood because 0, or no effect, does not fall within the confidence interval.
B) Reject the null hypothesis and conclude chocolate lowers mood because the confidence interval includes small numbers.
C) Fail to reject the null hypothesis because the confidence interval is positive.
D) Fail to reject the null hypothesis and conclude the effect size is small for this study.

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Multiple Choice

Q 52Q 52

A researcher investigates whether the extent to which people care about keeping their house clean and neat changes if they are given new things in that home.He follows eight families that were selected to receive home makeovers, assessing their cleanliness before the makeover and after.Given the confidence interval [-1.26, 0.95], what decision about the hypothesis should be made?
A) Reject the null hypothesis because the confidence interval includes the null hypothesized value.
B) Reject the null hypothesis and conclude that cleanliness did not change as a result of the manipulation.
C) Fail to reject the null hypothesis because 0 falls in the confidence interval.
D) Fail to reject the null hypothesis because the confidence interval has positive and negative values.

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Multiple Choice

Q 53Q 53

What would be the decision for a two-tailed paired-samples t test where the confidence interval was determined to be [-3.45, 2.61]?
A) reject the null hypothesis
B) fail to reject the null hypothesis
C) reject the research hypothesis
D) fail to reject the research hypothesis

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Multiple Choice

Q 54Q 54

What would be the decision for a two-tailed paired-samples t test where the confidence interval was determined to be [-3.45, -0.61]?
A) reject the null hypothesis
B) fail to reject the null hypothesis
C) reject the research hypothesis
D) fail to reject the research hypothesis

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Multiple Choice

Q 55Q 55

What would be the decision for a two-tailed paired-samples t test where the confidence interval was determined to be [1.34, 6.45]?
A) reject the null hypothesis
B) fail to reject the null hypothesis
C) reject the research hypothesis
D) fail to reject the research hypothesis

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Multiple Choice

Q 56Q 56

When conducting a paired-samples t test, one can assess the practical importance of the obtained results by calculating:
A) a hypothesis test.
B) an effect size measure.
C) post-hoc tests.
D) a confidence interval.

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Multiple Choice

Q 57Q 57

The correct formula for effect size using Cohen's d for a paired-samples t test is:
A) (M - )/s + .
B) (M - )/s.
C) (X - )/s.
D) ( - )/s.

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Multiple Choice

Q 58Q 58

The formula for calculating effect sizes for the paired-samples t test replaces the _____ symbol used in the formula for the t statistic with the _____ symbol.
A) s; s

_{M}B) s_{M}; s C) ; _{M}D) _{M}; Free

Multiple Choice

Q 59Q 59

Assume the following for a paired-samples t test: N = 19, M

_{difference}= 13.19, s = 22.3.What is the effect size using Cohen's d? A) 0.22 B) 0.41 C) 0.59 D) 2.58Free

Multiple Choice

Q 60Q 60

A paired-samples t test is reported as t(15) = 0.918, p > 0.05, d = 0.17.What is the effect size for this statistical test?
A) There is no effect size reported.
B) This is a small effect.
C) This is a medium effect.
D) This is a large effect.

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Multiple Choice

Q 61Q 61

Assume the following for a paired-samples t test: N = 12, M

_{difference}= 467.82, s = 280.50.What is the effect size statistic? A) 0.03 B) 0.60 C) 1.67 D) 3.34Free

Multiple Choice

Q 62Q 62

Assume the following for a paired-samples t test: N = 19, M

_{difference}= 13.19, s = 22.3.What is the size of the effect? A) small B) medium C) large D) no effectFree

Multiple Choice

Q 63Q 63

Assume the following for a paired-samples t test: N = 12, M

_{difference}= 467.82, s = 280.50.What is the size of the effect? A) small B) medium C) large D) no effectFree

Multiple Choice

Q 64Q 64

In a paired-samples t test, a possible confounding variable that can occur as a result of the within-groups design is:
A) counterbalancing.
B) repeated measures.
C) order effects.
D) error effects.

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Multiple Choice

Q 65Q 65

The possible threat of participants having experience with the variables in a within-groups design when they experience those variables for the second time is known as:
A) order effects.
B) counterbalancing.
C) repeated effects.
D) stimulus repeating.

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Multiple Choice

Q 66Q 66

A researcher is worried that performance on an aptitude test will improve simply because of repeat exposure to the instrument, which will cloud his ability to assess the impact of two unique educational interventions he wants to study.To help remove the effect of repeated exposure, the researcher could use:
A) repeated measures.
B) counterbalancing.
C) a within-groups design.
D) a single-sample t test.

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Multiple Choice

Q 67Q 67

The paired-samples t test allows one to assess how performance can differ between two groups of people over time.

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True False

Q 68Q 68

The paired-samples t test allows one to assess how performance can differ for one group of people over time.

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True False

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True False

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True False

Q 71Q 71

If the null hypothesis is true for a paired-samples t test, the mean of the distribution of mean differences is 0.

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True False

Q 72Q 72

For the paired-samples t test, one of the assumptions is that the variance of scores at time one is similar to the variance of scores at time two, known as homogeneity of variance.

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True False

Q 73Q 73

One expects children's vocabularies to increase over time, with, say, 200 new words per year established as the standard.The null hypothesis for a paired-samples t test that assesses 150 children at age 5 and again at age 6 would assume an average mean difference of 200 words.

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True False

Q 74Q 74

One expects children's vocabularies to increase over time, with, say, 200 new words per year established as the standard.The null hypothesis for a paired-samples t test that assesses 150 children at age 5 and again at age 6 would assume an average mean difference of zero words.

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True False

Q 75Q 75

The equation for the paired-samples t test is the same as that for the single-samples t test except that the data are now difference scores.

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True False

Q 76Q 76

The confidence interval for a paired-samples t test is centered around a hypothesized mean difference of zero.

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True False

Q 77Q 77

The sample mean difference should fall at the center of the confidence interval for a paired-samples t test.

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True False

Q 78Q 78

For the paired-samples t test, confidence interval calculations do not add any additional information.

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True False

Q 79Q 79

The effect size calculations for the paired-samples t test are interpreted in the same manner as those for the single-sample t test.

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True False

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True False

Q 81Q 81

Counterbalancing minimizes order effects due to the presentation of different levels of the independent variable.

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True False

Q 82Q 82

Counterbalancing minimizes order effects due to the presentation of different levels of the dependent variable.

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True False

Q 83Q 83

Doctors used a t test to compare cancer patients' recovery rates during time spent in the hospitals versus time spent in their own home to decide the best place for patients to be during recovery.Their study measured all patients' white blood cell counts while they were in the hospital and then again while all patients were at home.What type of design is this?
A) single-subjects
B) between-groups
C) within-groups
D) independent samples

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Multiple Choice

Q 84Q 84

A paired-samples t test is also known as a:
A) single-subject t test.
B) dependent-samples t test.
C) single-sample t test.
D) z test.

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Multiple Choice

Q 85Q 85

A group of rats ran faster after receiving a steroid drug supplement than they did earlier without any drug supplement.What type of statistical test should be reported with these results?
A) between-groups design
B) paired-samples t test
C) single-sample t test
D) z test

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Multiple Choice

Q 86Q 86

For the paired-samples t test, the comparison distribution:
A) is the same as that for a single-sample t test.
B) is the same as that for the z test.
C) contains sample means based on samples of the same size.
D) contains means of difference scores.

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Multiple Choice

Q 87Q 87

Twenty-four students were assessed on a mindfulness measure both before and after completing a semester-long meditative yoga class.The critical t values for a two-tailed paired-samples test based on their data, with a p level of 0.05, are:
A) -1.711 and 1.711.
B) -1.714 and 1.714.
C) -2.064 and 2.064.
D) -2.069 and 2.069.

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Multiple Choice

Q 88Q 88

Psychology students took longer to complete a quiz when music was playing in the background than when there was no background noise: t(14) = -6.23, p < 0.05.What is the sample size in this study?
A) 14
B) 15
C) 16
D) 20

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Multiple Choice

Q 89Q 89

What is the paired-samples t statistic when using M

_{difference}= 8.0, s = 5.8, N = 15? A) 1.50 B) 1.55 C) 4.76 D) 5.34Free

Multiple Choice

Q 90Q 90

What is the confidence interval for a paired-samples t test with a mean difference of 4.6, a standard error of 0.16, and 14 df?
A) [-0.36, 0.36]
B) [3.92, 4.18]
C) [4.24, 4.96]
D) [4.26, 4.94]

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Multiple Choice

Q 91Q 91

What is the correct formula for Cohen's d for a paired-samples t test?
A) (X - M)/N
B) (X - M)/(N - 1)
C) (M - )/s
D) (M - )/(s - 1)

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Multiple Choice

Q 92Q 92

A group of students in a research class develop an educational video about academic integrity.They are interested in whether their video can increase students' knowledge about the topic.They recruit 42 students, assess their knowledge about academic integrity, show the video, and then reassess knowledge with the same questionnaire used earlier.According to the phenomenon of order effects, performance on the test of knowledge may be:
A) higher on the first administration because students are fresh and not yet fatigued.
B) higher on its second administration simply because it has been seen once before.
C) lower on the first administration because the video has not yet been seen.
D) lower on the second administration because students may become tired.

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Multiple Choice

Q 93Q 93

In which statistical test does one calculate a difference score for each individual, take the mean of the difference scores, and perform a test on them to compare two sample means?
A) between-groups design
B) paired-samples t test
C) z test
D) single-sample t test

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Multiple Choice

Q 94Q 94

The major difference between the paired-samples t test and the single-samples t test is that in the paired-samples t test:
A) we must use raw scores.
B) we must create difference scores for every individual.
C) we must compare standard deviation difference scores.
D) there are no assumptions.

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Multiple Choice

Q 95Q 95

A researcher believes that a new training program will increase test scores.Previous research shows that test scores increase 8 points between the first and second administration of the test being used.This researcher believes his training program will cause a significant increase, beyond the expected 8 points.If a paired-samples t test is used by this researcher, what value would he expect to be at the center of the comparison distribution, a distribution of mean differences?
A) 8
B) 0
C) s divided by the square root of N
D) the sample mean

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Multiple Choice

Q 96Q 96

Credit card debt for 10 people was compared before a major economic crash (perhaps one like that of 2008) and then after economic recovery, let's say 5 years later.Which of the following is an appropriate null hypothesis for this research?
A) Economic recoveries have no impact on debt carried by citizens.
B) Credit card debt will be different after economic recovery compared to just prior to an economic crash.
C) Credit card debt increases over time.
D) Credit card debt before the economic crash will be approximately the same as that after the economic recovery.

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Multiple Choice

Q 97Q 97

The critical cutoffs for a two-tailed, paired-samples t test with N = 9, at a p level of 0.05, are:
A) -1.860 and 1.860.
B) -2.306 and 2.306.
C) -2.897 and 2.897.
D) -3.356 and 3.356.

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Multiple Choice

Q 98Q 98

A paired-samples t test results in the following statistic: t(6) = 2.41.Using this test result, what decision should be made about a two-tailed hypothesis test at p = 0.05?
A) Reject the null hypothesis and conclude the mean difference is greater than expected.
B) Reject the null hypothesis and conclude a strong effect size.
C) Fail to reject the null hypothesis because the sample size is too low to achieve statistical power.
D) Fail to reject the null hypothesis because the test statistic does not exceed the critical cutoff.

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Multiple Choice

Q 99Q 99

After performing a paired-samples t test as part of a hypothesis test, it is recommended by the APA that researchers also consider:
A) calculating a confidence interval and a measure of effect size.
B) performing a power analysis to assess the risk of Type I errors.
C) repeating the research with a between-groups design to avoid order effects.
D) running a replication to confirm the findings.

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Multiple Choice

Q 100Q 100

A researcher calculates a confidence interval for a paired-samples t test.That interval is centered around -8.32, which is the:
A) sample mean.
B) sample mean difference.
C) null hypothesized mean.
D) calculated t statistic.

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Multiple Choice

Q 101Q 101

A researcher reports a paired-samples t test as: t(13) = 2.37, p < 0.05, d = 0.81.The value of the effect size measure here is:
A) 0.05.
B) 0.81.
C) 2.37.
D) 13.

Free

Multiple Choice