Question 1

Two samples each have n = 4 scores.If the first sample has a variance of 10 and the second sample has a variance of 6,what is the estimated standard error for the sample mean difference?

Accepted Answer

A)  1
B)  2
C)  4
D)  Cannot determine without more information B

Question 2

The data from an independent-measures research study produce a sample mean difference of 6 points and an estimated standard error of 2 points.If there are n = 8 scores in each sample,what is the value for the t statistic?

Accepted Answer

A)  6/2
B)  6/4
C)  6/0.25
D)  6/0.50 A

Question 3

If both samples have the same number of scores (n),then the independent-measures t statistic will have df = 2n - 2.

Accepted Answer

A) True 
 B)False  True

Question 4

The data from an independent-measures research study produce a sample mean difference of 4 points and a pooled variance of 18.If there are n = 4 scores in each sample,what is the estimated standard error for the sample mean difference?

Accepted Answer

A)  3
B)  9
C)  12
D)  The square root of 12

Question 5

An independent-measures research study uses a total of 18 participants to compare two treatment conditions.If the results are used to construct a 90% confidence interval for the population mean difference,then the t values will be ±1.746.

Accepted Answer

A) True 
 B)False

Question 6

If other factors are held constant,which of the following sets of data is most likely to satisfy the homogeneity of variance assumption?

Accepted Answer

A)  A sample mean difference of 6 points and sample variances of 15 and 10
B)  A sample mean difference of 4 points and sample variances of 9 and 6
C)  A sample mean difference of 2 points and sample variances of 6 and 4
D)  The other 3 options are equally likely to satisfy the assumption.

Question 7

The results of an independent-measures research study are reported as "t(22)= 2.12,p < .05,two tails." For this study,what t values formed the boundaries for the critical region?

Accepted Answer

A)  ±2.080
B)  ±2.074
C)  ±2.069
D)  ±2.064

Question 8

If an independent-measures design is being used to compare two treatment conditions,then how many different groups of participants would be needed and how many scores would there be for each participant?

Accepted Answer

A)  1 group,1 score each
B)  2 groups,1 score each
C)  1 group,2 scores each
D)  2 groups,2 scores each

Question 9

An independent-measures study comparing two treatment conditions produces a t statistic with df = 18.If the two samples are the same size,how many participants were in each of the samples?

Accepted Answer

A)  9
B)  10
C)  19
D)  20

Question 10

An independent-measures research study uses two samples,each with n = 15 participants.If the data produce a t statistic of t = 2.760,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

Question 11

An independent-measures study has one sample with n = 6 and a second sample with n = 8 to compare two experimental treatments.What is the df value for the t statistic for this study?

Accepted Answer

A)  7
B)  12
C)  13
D)  14

Question 12

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 13

A researcher reports t(22)= 5.30,p < .01 for an independent-measures experiment.How many individuals participated in the entire experiment?

Accepted Answer

A)  20
B)  21
C)  23
D)  24

Question 14

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

Question 15

One sample of n = 8 scores has a variance of s2 = 6 and a second sample of n = 8 scores has s2 = 10.If the pooled variance is computed for these two samples,then the value obtained will be ______.

Accepted Answer

A)  closer to 6 than to 10
B)  closer to 10 than to 6
C)  exactly halfway between 6 and 10
D)  cannot be determined without more information

Question 16

For an independent-measures t statistic,the estimated standard error measures how much difference is reasonable to expect between the sample means for two samples selected from the same population.

Accepted Answer

A) True 
 B)False

Question 17

One sample has n = 7 scores with SS = 40,and a second sample has n = 5 scores with SS = 80.The pooled variance for these two samples is 120/10 = 12.

Accepted Answer

A) True 
 B)False

Question 18

An independent-measures research study uses a total of 40 participants to compare two treatment conditions.What is the df value for the t statistic for this study?

Accepted Answer

A)  18
B)  19
C)  38
D)  39

Question 19

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

Accepted Answer

A) True 
 B)False

Question 20

If two separate samples have M1 = 10 and M2 = 18 with a pooled variance of 16,then Cohen's d = 0.50.

Accepted Answer

A) True 
 B)False

Exam 10: The T Test for Two Independent Samples

Two samples each have n = 4 scores.If the first sample has a variance of 10 and the second sample has a variance of 6,what is the estimated standard error for the sample mean difference?

The data from an independent-measures research study produce a sample mean difference of 6 points and an estimated standard error of 2 points.If there are n = 8 scores in each sample,what is the value for the t statistic?

If both samples have the same number of scores (n),then the independent-measures t statistic will have df = 2n - 2.

The data from an independent-measures research study produce a sample mean difference of 4 points and a pooled variance of 18.If there are n = 4 scores in each sample,what is the estimated standard error for the sample mean difference?

An independent-measures research study uses a total of 18 participants to compare two treatment conditions.If the results are used to construct a 90% confidence interval for the population mean difference,then the t values will be ±1.746.

If other factors are held constant,which of the following sets of data is most likely to satisfy the homogeneity of variance assumption?

The results of an independent-measures research study are reported as "t(22) = 2.12,p < .05,two tails." For this study,what t values formed the boundaries for the critical region?

If an independent-measures design is being used to compare two treatment conditions,then how many different groups of participants would be needed and how many scores would there be for each participant?

An independent-measures study comparing two treatment conditions produces a t statistic with df = 18.If the two samples are the same size,how many participants were in each of the samples?

An independent-measures research study uses two samples,each with n = 15 participants.If the data produce a t statistic of t = 2.760,which of the following is the correct decision for a two-tailed hypothesis test?

An independent-measures study has one sample with n = 6 and a second sample with n = 8 to compare two experimental treatments.What is the df value for the t statistic for this study?

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

A researcher reports t(22) = 5.30,p < .01 for an independent-measures experiment.How many individuals participated in the entire experiment?

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

One sample of n = 8 scores has a variance of s² = 6 and a second sample of n = 8 scores has s² = 10.If the pooled variance is computed for these two samples,then the value obtained will be ______.

For an independent-measures t statistic,the estimated standard error measures how much difference is reasonable to expect between the sample means for two samples selected from the same population.

One sample has n = 7 scores with SS = 40,and a second sample has n = 5 scores with SS = 80.The pooled variance for these two samples is 120/10 = 12.

An independent-measures research study uses a total of 40 participants to compare two treatment conditions.What is the df value for the t statistic for this study?

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

If two separate samples have M₁ = 10 and M₂ = 18 with a pooled variance of 16,then Cohen's d = 0.50.