Question 1

Cohen's d is the:

Accepted Answer

A)  method for calculating confidence intervals for the z test. 
B)  difference between the sample means divided by the standard error. 
C)  standardized difference between group means. 
D)  measure of statistical power. 
A)  method for calculating confidence intervals for the z test. 
B)  difference between the sample means divided by the standard error. 
C)  standardized difference between group means. 
D)  measure of statistical power.

Question 2

The range of raw scores contained in an 80 percent confidence interval will be _____ the range of raw scores contained in a 95 percent confidence interval.

Accepted Answer

A)  larger than 
B)  smaller than 
C)  the same size as 
D)  smaller than or the same size as. 
A)  larger than 
B)  smaller than 
C)  the same size as 
D)  smaller than or the same size as.

Question 3

To remove the adjustment for the influence of sample size, Cohen's d uses the _____ rather than the _____ as part of its formula.

Accepted Answer

A)  standard error; standard deviation 
B)  standard deviation; standard error 
C)  raw scores; standard scores 
D)  variance; raw scores 
A)  standard error; standard deviation 
B)  standard deviation; standard error 
C)  raw scores; standard scores 
D)  variance; raw scores

Question 4

Cohen's d is one measure of:

Accepted Answer

A)  statistical significance. 
B)  effect size. 
C)  clinical significance. 
D)  sample characteristics. 
A)  statistical significance. 
B)  effect size. 
C)  clinical significance. 
D)  sample characteristics.

Question 5

Why are effect sizes rather than test statistics used when comparing study results?

Accepted Answer

A)  Effect sizes, unlike test statistics, are not affected by sample size and thus ensure a fair comparison. 
B)  It is easier to average effect size than it is to average test statistics. 
C)  Effect sizes are based on standard error, while test statistics are based on standard deviation. 
D)  Effect sizes, unlike test statistics, account for sample size, thus ensuring an accurate comparison. 
A)  Effect sizes, unlike test statistics, are not affected by sample size and thus ensure a fair comparison. 
B)  It is easier to average effect size than it is to average test statistics. 
C)  Effect sizes are based on standard error, while test statistics are based on standard deviation. 
D)  Effect sizes, unlike test statistics, account for sample size, thus ensuring an accurate comparison.

Question 6

The statement "The findings based on a sample of 1000 participants were statistically significant, providing evidence for the hypothesis" would be strengthened by:

Accepted Answer

A)  using convenience sampling. 
B)  hypothesis testing. 
C)  measuring effect sizes. 
D)  sampling university students. 
A)  using convenience sampling. 
B)  hypothesis testing. 
C)  measuring effect sizes. 
D)  sampling university students.

Question 7

Mehl (2007) published a study in the journal Science reporting the results of an extensive study of 396 men and women comparing the number of words uttered per day by each sex.He found that on average women uttered 16,215 words a day and men uttered 15,669 words a day.The effect size calculated on the basis of his findings is Cohen's d = 0.07.This effect size indicates that the:

Accepted Answer

A)  number of words uttered by the men and women significantly differed from one another. 
B)  women uttered a significantly greater number of words in a day than did the men. 
C)  means of the men and women overlap by only 7 percent. 
D)  means of the men and women are not even one-tenth of 1 standard deviation apart. 
A)  number of words uttered by the men and women significantly differed from one another. 
B)  women uttered a significantly greater number of words in a day than did the men. 
C)  means of the men and women overlap by only 7 percent. 
D)  means of the men and women are not even one-tenth of 1 standard deviation apart.

Question 8

Recent research published by Frumin and colleagues (2011) in the journal Science addresses whether females' tears have an effect on males.Imagine that exposure to tears lowered self-rated sexual arousal by 1.27 points, with a margin of error of 0.32 points.The interval estimate is:

Accepted Answer

A)  1.27. 
B)  +/- 0.32. 
C)  [0.95, 1.59]. 
D)  0.32. 
A)  1.27. 
B)  +/- 0.32. 
C)  [0.95, 1.59]. 
D)  0.32.

Question 9

If the sample mean is 56.2, with an upper limit to the confidence interval of 62.74, what is the lower limit?

Accepted Answer

A)  6.54 
B)  49.66 
C)  52.46 
D)  56.20 
A)  6.54 
B)  49.66 
C)  52.46 
D)  56.20

Question 10

Assume for a given study that the null hypothesis asserts the expected value of a phenomenon is 10.A research study results in a 95 percent confidence interval reported as [7.142, 9.865].What decision should be made based on this confidence interval?

Accepted Answer

A)  Reject the null hypothesis. 
B)  Fail to reject the null hypothesis. 
C)  Retain the null hypothesis. 
D)  Perform a hypothesis test before making a decision. 
A)  Reject the null hypothesis. 
B)  Fail to reject the null hypothesis. 
C)  Retain the null hypothesis. 
D)  Perform a hypothesis test before making a decision.

Question 11

As sample size increases, the standard error decreases, resulting in a smaller test statistic.

Accepted Answer

A) True 
 B)False

Question 12

Mehl (2007) published a study in the journal Science reporting the results of an extensive study of 396 men and women comparing the number of words uttered per day by each sex.He found that on average women uttered 16,215 words a day and men uttered 15,669 words a day.The effect size calculated on the basis of his findings is Cohen's d = 0.07.According to Cohen's conventions for interpreting d, this effect is:

Accepted Answer

A)  small. 
B)  medium. 
C)  large. 
D)  so small as to be considered virtually no effect. 
A)  small. 
B)  medium. 
C)  large. 
D)  so small as to be considered virtually no effect.

Question 13

Effect size indicates the size of the difference between the population and the null hypothesized value.

Accepted Answer

A) True 
 B)False

Question 14

Published literature tends to include significant findings, where the data were sufficient to reject the null hypothesis.This can lead to an inflated estimate of effect size when computing a meta-analysis.Rosenthal suggested that researchers test the level of inflation of their effect size calculations by:

Accepted Answer

A)  conducting additional research that would more clearly assess the relationship between variables. 
B)  pressuring scholarly journals to publish more null findings. 
C)  computing a file drawer analysis to see how many null findings would be needed to remove the statistical significance found. 
D)  including studies in their meta-analysis that have strong effects only. 
A)  conducting additional research that would more clearly assess the relationship between variables. 
B)  pressuring scholarly journals to publish more null findings. 
C)  computing a file drawer analysis to see how many null findings would be needed to remove the statistical significance found. 
D)  including studies in their meta-analysis that have strong effects only.

Question 15

Measures of effect size:

Accepted Answer

A)  are unaffected by sample size. 
B)  increase as sample size increases. 
C)  decrease as the difference between population means increases. 
D)  do not rely on sample means. 
A)  are unaffected by sample size. 
B)  increase as sample size increases. 
C)  decrease as the difference between population means increases. 
D)  do not rely on sample means.

Question 16

Ideally, a statistical power analysis should be conducted _____ the study.

Accepted Answer

A)  during 
B)  before 
C)  after 
D)  throughout 
A)  during 
B)  before 
C)  after 
D)  throughout

Question 17

Recent research published by Frumin and colleagues (2011) in the journal Science addresses whether females' tears have an effect on males.Imagine that exposure to tears lowered self-rated sexual arousal by 1.27 points, with a margin of error of 0.32 points.The point estimate is:

Accepted Answer

A)  1.27. 
B)  1.27 +/- 0.32. 
C)  [0.95, 1.59]. 
D)  0.32. 
A)  1.27. 
B)  1.27 +/- 0.32. 
C)  [0.95, 1.59]. 
D)  0.32.

Question 18

Imagine that a study of memory and aging finds that younger participants correctly recall 55 percent of studied words, older participants correctly recall 42 percent of studied words, and the size of this effect is Cohen's d = 0.49.This effect size indicates that the memory performance of:

Accepted Answer

A)  older participants is approximately half a standard deviation above that of younger participants. 
B)  older participants is approximately half a standard deviation below that of younger participants. 
C)  younger participants is approximately half a standard deviation below that of older participants. 
D)  younger participants is significantly lower than that of older participants. 
A)  older participants is approximately half a standard deviation above that of younger participants. 
B)  older participants is approximately half a standard deviation below that of younger participants. 
C)  younger participants is approximately half a standard deviation below that of older participants. 
D)  younger participants is significantly lower than that of older participants.

Question 19

Power can be thought of as the percentage of the distribution of means, centered around the sample mean, that falls:

Accepted Answer

A)  outside of the null hypothesized distribution. 
B)  below the mean of the null hypothesized distribution. 
C)  above two standard deviations from the sample mean. 
D)  within the critical cutoff regions, where the null hypothesis can be rejected. 
A)  outside of the null hypothesized distribution. 
B)  below the mean of the null hypothesized distribution. 
C)  above two standard deviations from the sample mean. 
D)  within the critical cutoff regions, where the null hypothesis can be rejected.

Question 20

It becomes progressively easier to declare statistical significance as the _____ increases.

Accepted Answer

A)  standard error 
B)  value of the critical cutoff 
C)  sample size 
D)  number of items on the instrument 
A)  standard error 
B)  value of the critical cutoff 
C)  sample size 
D)  number of items on the instrument

Cohen's d is the:

The range of raw scores contained in an 80 percent confidence interval will be _____ the range of raw scores contained in a 95 percent confidence interval.

To remove the adjustment for the influence of sample size, Cohen's d uses the _ rather than the _ as part of its formula.

Cohen's d is one measure of:

Why are effect sizes rather than test statistics used when comparing study results?

The statement "The findings based on a sample of 1000 participants were statistically significant, providing evidence for the hypothesis" would be strengthened by:

Recent research published by Frumin and colleagues (2011) in the journal Science addresses whether females' tears have an effect on males.Imagine that exposure to tears lowered self-rated sexual arousal by 1.27 points, with a margin of error of 0.32 points.The interval estimate is:

If the sample mean is 56.2, with an upper limit to the confidence interval of 62.74, what is the lower limit?

Assume for a given study that the null hypothesis asserts the expected value of a phenomenon is 10.A research study results in a 95 percent confidence interval reported as [7.142, 9.865].What decision should be made based on this confidence interval?

As sample size increases, the standard error decreases, resulting in a smaller test statistic.

Effect size indicates the size of the difference between the population and the null hypothesized value.

Measures of effect size:

Ideally, a statistical power analysis should be conducted _____ the study.

Recent research published by Frumin and colleagues (2011) in the journal Science addresses whether females' tears have an effect on males.Imagine that exposure to tears lowered self-rated sexual arousal by 1.27 points, with a margin of error of 0.32 points.The point estimate is:

Imagine that a study of memory and aging finds that younger participants correctly recall 55 percent of studied words, older participants correctly recall 42 percent of studied words, and the size of this effect is Cohen's d = 0.49.This effect size indicates that the memory performance of:

Power can be thought of as the percentage of the distribution of means, centered around the sample mean, that falls:

It becomes progressively easier to declare statistical significance as the _____ increases.

An Introduction to Statistics and Research Design

Frequency Distributions

Visual Displays of Data

Central Tendency and Variability

Sampling and Probability

The Normal Curve, Standardization and Z Scores

Hypothesis Testing With Z Tests

The Single-Sample T Test

The Paired-Samples T Test

The Independent-Samples T Test

One-Way Between-Groups Anova

One-Way Within-Groups Anova

Two-Way Between-Groups Anova

Correlation

Regression

Chi-Square Tess

Choosing and Reporting Statistics

Filters

Exam 8: Confidence Intervals, Effect Size, and Statistical Power

Cohen's d is the:

The range of raw scores contained in an 80 percent confidence interval will be _____ the range of raw scores contained in a 95 percent confidence interval.

To remove the adjustment for the influence of sample size, Cohen's d uses the _____ rather than the _____ as part of its formula.

Cohen's d is one measure of:

Why are effect sizes rather than test statistics used when comparing study results?

The statement "The findings based on a sample of 1000 participants were statistically significant, providing evidence for the hypothesis" would be strengthened by:

Recent research published by Frumin and colleagues (2011) in the journal Science addresses whether females' tears have an effect on males.Imagine that exposure to tears lowered self-rated sexual arousal by 1.27 points, with a margin of error of 0.32 points.The interval estimate is:

If the sample mean is 56.2, with an upper limit to the confidence interval of 62.74, what is the lower limit?

Assume for a given study that the null hypothesis asserts the expected value of a phenomenon is 10.A research study results in a 95 percent confidence interval reported as [7.142, 9.865].What decision should be made based on this confidence interval?

As sample size increases, the standard error decreases, resulting in a smaller test statistic.

Effect size indicates the size of the difference between the population and the null hypothesized value.

Measures of effect size:

Ideally, a statistical power analysis should be conducted _____ the study.

Recent research published by Frumin and colleagues (2011) in the journal Science addresses whether females' tears have an effect on males.Imagine that exposure to tears lowered self-rated sexual arousal by 1.27 points, with a margin of error of 0.32 points.The point estimate is:

Imagine that a study of memory and aging finds that younger participants correctly recall 55 percent of studied words, older participants correctly recall 42 percent of studied words, and the size of this effect is Cohen's d = 0.49.This effect size indicates that the memory performance of:

Power can be thought of as the percentage of the distribution of means, centered around the sample mean, that falls:

It becomes progressively easier to declare statistical significance as the _____ increases.

An Introduction to Statistics and Research Design

Frequency Distributions

Visual Displays of Data

Central Tendency and Variability

Sampling and Probability

The Normal Curve, Standardization and Z Scores

Hypothesis Testing With Z Tests

The Single-Sample T Test

The Paired-Samples T Test

The Independent-Samples T Test

One-Way Between-Groups Anova

One-Way Within-Groups Anova

Two-Way Between-Groups Anova

Correlation

Regression

Chi-Square Tess

Choosing and Reporting Statistics

Filters

To remove the adjustment for the influence of sample size, Cohen's d uses the _ rather than the _ as part of its formula.