Question 1

If the two samples are the same size, then the pooled variance will equal the average of the two sample variances.

Accepted Answer

A) True 
 B)False  True

Question 2

The 95% confidence interval for the difference between two treatment means extends from -2.50 to +5.50.Based on this information, you can conclude that there is no significant difference between the treatments at the .05 level of significance.

Accepted Answer

A) True 
 B)False  True

Question 3

The null hypothesis for the independent-measures t test states that there is no difference between the two sample means.

Accepted Answer

A) True 
 B)False  False

Question 4

The estimated standard error for the independent-measures t statistic provides a measure of how much difference should exist, on average, between two sample means for samples selected from the same population.

Accepted Answer

A) True 
 B)False

Question 5

An independent-measures research study uses two samples, each with n = 12 participants.If the data produce a t statistic of t = 2.08, then which of the following is the correct decision for a two-tailed hypothesis test?

Accepted Answer

A) Reject the null hypothesis with α = .05 but fail to reject with α = .01. 
B) Fail to reject the null hypothesis with either α = .05 or α = .01. 
C) Reject the null hypothesis with either α = .05 or α = .01. 
D) Cannot answer without additional information 
A) Reject the null hypothesis with α = .05 but fail to reject with α = .01. 
B) Fail to reject the null hypothesis with either α = .05 or α = .01. 
C) Reject the null hypothesis with either α = .05 or α = .01. 
D) Cannot answer without additional information

Question 6

If two samples each have s2 = 10, then the pooled variance will be equal to 20.

Accepted Answer

A) True 
 B)False

Question 7

One sample has a variance of s2 = 10 and a second sample has a variance of s2 = 6.If the two samples have the same number of scores, what is the pooled variance for the two samples?

Accepted Answer

A) 4 
B) 8 
C) 14 
D) Cannot answer without knowing the sample size. 
A) 4 
B) 8 
C) 14 
D) Cannot answer without knowing the sample size.

Question 8

For an independent-measures research study, what is measured by Cohen's d or r2?

Accepted Answer

A) the risk of a Type I error 
B) the risk of a Type II error 
C) the size of the difference between the two treatments 
D) whether the difference between the two treatments is likely to have occurred by chance 
A) the risk of a Type I error 
B) the risk of a Type II error 
C) the size of the difference between the two treatments 
D) whether the difference between the two treatments is likely to have occurred by chance

Question 9

For an independent-measures t statistic, the estimated standard error measures how much difference is reasonable to expect between the two sample means if the null hypothesis is true.

Accepted Answer

A) True 
 B)False

Question 10

For the independent-measures t statistic, what is the effect of increasing the sample variances?

Accepted Answer

A) increase the likelihood of rejecting H0 and increase measures of effect size 
B) increase the likelihood of rejecting H0 and decrease measures of effect size 
C) decrease the likelihood of rejecting H0 and increase measures of effect size 
D) decrease the likelihood of rejecting H0 and decrease measures of effect size 
A) increase the likelihood of rejecting H0 and increase measures of effect size 
B) increase the likelihood of rejecting H0 and decrease measures of effect size 
C) decrease the likelihood of rejecting H0 and increase measures of effect size 
D) decrease the likelihood of rejecting H0 and decrease measures of effect size

Question 11

For an independent-measures study, the width of a confidence interval estimating µ1 - µ2 depends of the size of the difference between M1 and M2.

Accepted Answer

A) True 
 B)False

Question 12

For a hypothesis test with the independent-measures t statistic, the null hypothesis states that the two population means are the same and the homogeneity assumption states that the two population variances are the same.

Accepted Answer

A) True 
 B)False

Question 13

An independent-measures study has one sample with n = 10 and a second sample with n = 15 to compare two experimental treatments.What is the df value for the t statistic for this study?

Accepted Answer

A) 23 
B) 24 
C) 26 
D) 27 
A) 23 
B) 24 
C) 26 
D) 27

Question 14

An independent-measures research study uses two samples, each with n = 12 participants.If the data produce a t statistic of t = 2.50, then which of the following is the correct decision for a two-tailed hypothesis test?

Accepted Answer

A) Reject the null hypothesis with α = .05 but fail to reject with α = .01. 
B) Reject the null hypothesis with either α = .05 or α = .01. 
C) Fail to reject the null hypothesis with either α = .05 or α = .01. 
D) Cannot answer without additional information 
A) Reject the null hypothesis with α = .05 but fail to reject with α = .01. 
B) Reject the null hypothesis with either α = .05 or α = .01. 
C) Fail to reject the null hypothesis with either α = .05 or α = .01. 
D) Cannot answer without additional information

Question 15

For an independent-measures t statistic, you typically must compute the pooled variance before calculating the estimated standard error.

Accepted Answer

A) True 
 B)False

Question 16

Two samples, each with n = 5 scores, have a pooled variance of 40.What is the estimated standard error for the sample mean difference?

Accepted Answer

A) 4 
B) 8 
C) 10 
D) √20 
A) 4 
B) 8 
C) 10 
D) √20

Question 17

Which set of sample characteristics is most likely to produce a significant value for the independent-measures t statistic?

Accepted Answer

A) a small mean difference and small sample variances 
B) a large mean difference and small sample variances 
C) a small mean difference and large sample variances 
D) a large mean difference and large sample variances 
A) a small mean difference and small sample variances 
B) a large mean difference and small sample variances 
C) a small mean difference and large sample variances 
D) a large mean difference and large sample variances

Question 18

Which combination of factors is most likely to produce a significant value for an independent-measures t statistic?

Accepted Answer

A) large samples and large variance 
B) large samples and small variance 
C) small samples and large variance 
D) small samples and small variance 
A) large samples and large variance 
B) large samples and small variance 
C) small samples and large variance 
D) small samples and small variance

Question 19

If n = 15 for each sample, which of the following sets of data provides the clearest difference between the two samples?

Accepted Answer

A) a sample mean difference of 5 points with s2 = 5 for both samples 
B) a sample mean difference of 5 points with s2 = 10 for both samples 
C) a sample mean difference of 10 points with s2 = 5 for both samples 
D) a sample mean difference of 10 points with s2 = 10 for both samples 
A) a sample mean difference of 5 points with s2 = 5 for both samples 
B) a sample mean difference of 5 points with s2 = 10 for both samples 
C) a sample mean difference of 10 points with s2 = 5 for both samples 
D) a sample mean difference of 10 points with s2 = 10 for both samples

Question 20

Two samples, each with n = 9 scores, produce an independent-measures t statistic of t = 2.00.If the effect size is measured using r2, what is the value of r2?

Accepted Answer

A) 4/16 
B) 4/20 
C) 2/16 
D) 2/18 
A) 4/16 
B) 4/20 
C) 2/16 
D) 2/18

If the two samples are the same size, then the pooled variance will equal the average of the two sample variances.

The 95% confidence interval for the difference between two treatment means extends from -2.50 to +5.50.Based on this information, you can conclude that there is no significant difference between the treatments at the .05 level of significance.

The null hypothesis for the independent-measures t test states that there is no difference between the two sample means.

The estimated standard error for the independent-measures t statistic provides a measure of how much difference should exist, on average, between two sample means for samples selected from the same population.

An independent-measures research study uses two samples, each with n = 12 participants.If the data produce a t statistic of t = 2.08, then which of the following is the correct decision for a two-tailed hypothesis test?

If two samples each have s² = 10, then the pooled variance will be equal to 20.

One sample has a variance of s² = 10 and a second sample has a variance of s² = 6.If the two samples have the same number of scores, what is the pooled variance for the two samples?

For an independent-measures research study, what is measured by Cohen's d or r²?

For an independent-measures t statistic, the estimated standard error measures how much difference is reasonable to expect between the two sample means if the null hypothesis is true.

For the independent-measures t statistic, what is the effect of increasing the sample variances?

For an independent-measures study, the width of a confidence interval estimating µ₁ - µ₂ depends of the size of the difference between M₁ and M₂.

For a hypothesis test with the independent-measures t statistic, the null hypothesis states that the two population means are the same and the homogeneity assumption states that the two population variances are the same.

An independent-measures study has one sample with n = 10 and a second sample with n = 15 to compare two experimental treatments.What is the df value for the t statistic for this study?

An independent-measures research study uses two samples, each with n = 12 participants.If the data produce a t statistic of t = 2.50, then which of the following is the correct decision for a two-tailed hypothesis test?

For an independent-measures t statistic, you typically must compute the pooled variance before calculating the estimated standard error.

Two samples, each with n = 5 scores, have a pooled variance of 40.What is the estimated standard error for the sample mean difference?

Which set of sample characteristics is most likely to produce a significant value for the independent-measures t statistic?

Which combination of factors is most likely to produce a significant value for an independent-measures t statistic?

If n = 15 for each sample, which of the following sets of data provides the clearest difference between the two samples?

Two samples, each with n = 9 scores, produce an independent-measures t statistic of t = 2.00.If the effect size is measured using r², what is the value of r²?

Introduction to Statistics

Frequency Distributions

Central Tendency

Variability

Z-Scores

Probability

The Distribution of Sample Means

Introduction to Hypothesis Testing

Introduction to the T Statistic

The T Test for Two Related Samples

Introduction to Analysis of Variance

Repeated-Measures Anova

Two-Factor Analysis of Variance

Correlation

Introduction to Regression

Chi-Square Tests

The Binomial Test

Choosing the Right Statistics

Filters

Exam 10: The T Test for Two Independent Samples

If the two samples are the same size, then the pooled variance will equal the average of the two sample variances.

The 95% confidence interval for the difference between two treatment means extends from -2.50 to +5.50.Based on this information, you can conclude that there is no significant difference between the treatments at the .05 level of significance.

The null hypothesis for the independent-measures t test states that there is no difference between the two sample means.

The estimated standard error for the independent-measures t statistic provides a measure of how much difference should exist, on average, between two sample means for samples selected from the same population.

An independent-measures research study uses two samples, each with n = 12 participants.If the data produce a t statistic of t = 2.08, then which of the following is the correct decision for a two-tailed hypothesis test?

If two samples each have s2 = 10, then the pooled variance will be equal to 20.

One sample has a variance of s2 = 10 and a second sample has a variance of s2 = 6.If the two samples have the same number of scores, what is the pooled variance for the two samples?

For an independent-measures research study, what is measured by Cohen's d or r2?

For an independent-measures t statistic, the estimated standard error measures how much difference is reasonable to expect between the two sample means if the null hypothesis is true.

For the independent-measures t statistic, what is the effect of increasing the sample variances?

For an independent-measures study, the width of a confidence interval estimating µ1 - µ2 depends of the size of the difference between M1 and M2.

For a hypothesis test with the independent-measures t statistic, the null hypothesis states that the two population means are the same and the homogeneity assumption states that the two population variances are the same.

An independent-measures study has one sample with n = 10 and a second sample with n = 15 to compare two experimental treatments.What is the df value for the t statistic for this study?

An independent-measures research study uses two samples, each with n = 12 participants.If the data produce a t statistic of t = 2.50, then which of the following is the correct decision for a two-tailed hypothesis test?

For an independent-measures t statistic, you typically must compute the pooled variance before calculating the estimated standard error.

Two samples, each with n = 5 scores, have a pooled variance of 40.What is the estimated standard error for the sample mean difference?

Which set of sample characteristics is most likely to produce a significant value for the independent-measures t statistic?

Which combination of factors is most likely to produce a significant value for an independent-measures t statistic?

If n = 15 for each sample, which of the following sets of data provides the clearest difference between the two samples?

Two samples, each with n = 9 scores, produce an independent-measures t statistic of t = 2.00.If the effect size is measured using r2, what is the value of r2?

Introduction to Statistics

Frequency Distributions

Central Tendency

Variability

Z-Scores

Probability

The Distribution of Sample Means

Introduction to Hypothesis Testing

Introduction to the T Statistic

The T Test for Two Related Samples

Introduction to Analysis of Variance

Repeated-Measures Anova

Two-Factor Analysis of Variance

Correlation

Introduction to Regression

Chi-Square Tests

The Binomial Test

Choosing the Right Statistics

Filters

If two samples each have s² = 10, then the pooled variance will be equal to 20.

One sample has a variance of s² = 10 and a second sample has a variance of s² = 6.If the two samples have the same number of scores, what is the pooled variance for the two samples?

For an independent-measures research study, what is measured by Cohen's d or r²?

For an independent-measures study, the width of a confidence interval estimating µ₁ - µ₂ depends of the size of the difference between M₁ and M₂.

Two samples, each with n = 9 scores, produce an independent-measures t statistic of t = 2.00.If the effect size is measured using r², what is the value of r²?