Question 1

When calculating a confidence interval for an independent-samples t test, replace the sample mean difference with the population mean difference.

Accepted Answer

A) True 
 B)False  False

Question 2

s2pooled is the symbol for:

Accepted Answer

A)  variance. 
B)  pooled variance. 
C)  standard deviation. 
D)  pooled mean. 
A)  variance. 
B)  pooled variance. 
C)  standard deviation. 
D)  pooled mean. B

Question 3

When conducting an independent-samples t test, it is necessary to have an equal number of participants in both groups.

Accepted Answer

A) True 
 B)False  False

Question 4

A clinical researcher was interested in determining whether her interventions for depression were effective in minimizing depression symptoms among her participants.To assess the effectiveness of her 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 her treatment was effective.Which statistical test was the researcher MOST likely to have used to test her hypothesis?

Accepted Answer

A)  single-sample t test 
B)  z test 
C)  independent-samples t test 
D)  paired-samples t test 
A)  single-sample t test 
B)  z test 
C)  independent-samples t test 
D)  paired-samples t test

Question 5

Why is it necessary to use the pooled variance when conducting an independent-samples t test?

Accepted Answer

A)  We are working with two samples, and an estimate of spread based on two samples is likely to be more accurate than an estimate of spread based on a single sample. 
B)  It is necessary to estimate the standard deviation of the two samples in order to compare the two samples to one another. 
C)  Estimating the spread of the sample using the standard deviation increases the generalizability of results. 
D)  Using the pooled variance helps the researcher identify skewness. 
A)  We are working with two samples, and an estimate of spread based on two samples is likely to be more accurate than an estimate of spread based on a single sample. 
B)  It is necessary to estimate the standard deviation of the two samples in order to compare the two samples to one another. 
C)  Estimating the spread of the sample using the standard deviation increases the generalizability of results. 
D)  Using the pooled variance helps the researcher identify skewness.

Question 6

Bayesian statistics help us account for both prior beliefs and chance.

Accepted Answer

A) True 
 B)False

Question 7

The formula for the total degrees of freedom for the independent-samples t test is:

Accepted Answer

A)  N. 
B)  dfX + dfY. 
C)  N - 1. 
D)  (N - 1)(N - 1). 
A)  N. 
B)  dfX + dfY. 
C)  N - 1. 
D)  (N - 1)(N - 1).

Question 8

The comparison distribution for an independent-samples t test is a distribution of:

Accepted Answer

A)  differences between means. 
B)  means. 
C)  mean of difference of scores. 
D)  scores. 
A)  differences between means. 
B)  means. 
C)  mean of difference of scores. 
D)  scores.

Question 9

In order to report the exact p value associated with the test statistic for an independent-samples t test, we need to:

Accepted Answer

A)  use software to obtain the value. 
B)  record the value from the t table under the 0.05 p level. 
C)  compute Cohen's d. 
D)  record the value from the t table under the 0.01 p level. 
A)  use software to obtain the value. 
B)  record the value from the t table under the 0.05 p level. 
C)  compute Cohen's d. 
D)  record the value from the t table under the 0.01 p level.

Question 10

When statisticians describe pooling the variances, they mean:

Accepted Answer

A)  adding the standard deviations of the two samples. 
B)  adding the variances of the two samples. 
C)  taking the average of the two variances, accounting for sample size. 
D)  taking the average of the two variances, disregarding sample size. 
A)  adding the standard deviations of the two samples. 
B)  adding the variances of the two samples. 
C)  taking the average of the two variances, accounting for sample size. 
D)  taking the average of the two variances, disregarding sample size.

Question 11

Some researchers believe hypothesis testing should completely replace Bayesian statistics.

Accepted Answer

A) True 
 B)False

Question 12

In a(n) _____, a within-groups design with two groups is used to compare the distribution of mean difference scores.

Accepted Answer

A)  single-sample t test 
B)  z test 
C)  independent-samples t test 
D)  paired-samples t test 
A)  single-sample t test 
B)  z test 
C)  independent-samples t test 
D)  paired-samples t test

Question 13

A study found statistically significant results for a hypothesis tested with an independent-samples t test.The author of the study reported her effect size for the test as 0.60.According to Cohen's convention, this effect size is considered:

Accepted Answer

A)  small. 
B)  medium. 
C)  large. 
D)  to have no overlap. 
A)  small. 
B)  medium. 
C)  large. 
D)  to have no overlap.

Question 14

The results of an independent-samples t-test were t(19) = 4.02, p < 0.05.These results are:

Accepted Answer

A)  statistically significant. 
B)  generalizable. 
C)  meaningful. 
D)  not statistically significant. 
A)  statistically significant. 
B)  generalizable. 
C)  meaningful. 
D)  not statistically significant.

Question 15

The confidence interval for an independent-samples t test is an interval estimate.

Accepted Answer

A) True 
 B)False

Question 16

Which of these illustrates a statistically insignificant result for an independent-samples t test?

Accepted Answer

A)  t(N - 1) = 3.89, p  0.05 
D)  t(N - 2) = 3.89, p < 0.05 
A)  t(N - 1) = 3.89, p  0.05 
D)  t(N - 2) = 3.89, p < 0.05

Question 17

Dr.Jameson wanted to know if IQ scores differed between male and female participants in his study.He gave 28 participants an IQ test and then compared IQ scores for gender differences.He hypothesized that there would be a statistically significant gender difference in IQ scores.Contrary to Dr.Jameson's hypothesis, there were no differences in IQ scores between men and women in his study.What is the dependent variable in this study?

Accepted Answer

A)  IQ scores 
B)  sample size of 28 
C)  gender 
D)  participants 
A)  IQ scores 
B)  sample size of 28 
C)  gender 
D)  participants

Question 18

To calculate a confidence interval for an independent-samples t test, use the:

Accepted Answer

A)  difference between means. 
B)  difference between medians. 
C)  mean of the first group only. 
D)  mean of the second group only. 
A)  difference between means. 
B)  difference between medians. 
C)  mean of the first group only. 
D)  mean of the second group only.

Question 19

_____ is a weighted average of the two estimates of _____.

Accepted Answer

A)  Pooled variance; variance 
B)  Variance; pooled variance 
C)  Pooled variance; standard deviation 
D)  Standard deviation; pooled variance 
A)  Pooled variance; variance 
B)  Variance; pooled variance 
C)  Pooled variance; standard deviation 
D)  Standard deviation; pooled variance

Question 20

Researchers were interested in whether relaxation training decreases the number of headaches a person experiences.They randomly assigned 20 participants to a control group (no relaxation training) or a relaxation training group and noted the change in number of headaches each group reported from the week before training to the week after training.The independent variable in this study is:

Accepted Answer

A)  training type. 
B)  number of headaches. 
C)  control group. 
D)  relaxation training. 
A)  training type. 
B)  number of headaches. 
C)  control group. 
D)  relaxation training.

When calculating a confidence interval for an independent-samples t test, replace the sample mean difference with the population mean difference.

s²_pooled is the symbol for:

When conducting an independent-samples t test, it is necessary to have an equal number of participants in both groups.

Why is it necessary to use the pooled variance when conducting an independent-samples t test?

Bayesian statistics help us account for both prior beliefs and chance.

The formula for the total degrees of freedom for the independent-samples t test is:

The comparison distribution for an independent-samples t test is a distribution of:

In order to report the exact p value associated with the test statistic for an independent-samples t test, we need to:

When statisticians describe pooling the variances, they mean:

Some researchers believe hypothesis testing should completely replace Bayesian statistics.

In a(n) _____, a within-groups design with two groups is used to compare the distribution of mean difference scores.

A study found statistically significant results for a hypothesis tested with an independent-samples t test.The author of the study reported her effect size for the test as 0.60.According to Cohen's convention, this effect size is considered:

The results of an independent-samples t-test were t(19) = 4.02, p < 0.05.These results are:

The confidence interval for an independent-samples t test is an interval estimate.

Which of these illustrates a statistically insignificant result for an independent-samples t test?

To calculate a confidence interval for an independent-samples t test, use the:

_ is a weighted average of the two estimates of _.

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

Confidence Intervals, Effect Size, and Statistical Power

The Single-Sample T Test

The Paired-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 11: The Independent-Samples T Test

When calculating a confidence interval for an independent-samples t test, replace the sample mean difference with the population mean difference.

s2pooled is the symbol for:

When conducting an independent-samples t test, it is necessary to have an equal number of participants in both groups.

Why is it necessary to use the pooled variance when conducting an independent-samples t test?

Bayesian statistics help us account for both prior beliefs and chance.

The formula for the total degrees of freedom for the independent-samples t test is:

The comparison distribution for an independent-samples t test is a distribution of:

In order to report the exact p value associated with the test statistic for an independent-samples t test, we need to:

When statisticians describe pooling the variances, they mean:

Some researchers believe hypothesis testing should completely replace Bayesian statistics.

In a(n) _____, a within-groups design with two groups is used to compare the distribution of mean difference scores.

A study found statistically significant results for a hypothesis tested with an independent-samples t test.The author of the study reported her effect size for the test as 0.60.According to Cohen's convention, this effect size is considered:

The results of an independent-samples t-test were t(19) = 4.02, p < 0.05.These results are:

The confidence interval for an independent-samples t test is an interval estimate.

Which of these illustrates a statistically insignificant result for an independent-samples t test?

To calculate a confidence interval for an independent-samples t test, use the:

_____ is a weighted average of the two estimates of _____.

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

Confidence Intervals, Effect Size, and Statistical Power

The Single-Sample T Test

The Paired-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

s²_pooled is the symbol for:

_ is a weighted average of the two estimates of _.