Question 1

One sample has s² = 12,and a second sample has s² = 15.The pooled variance for these two samples will be between 12 and 15.

Accepted Answer

A) True 
 B)False  True

Question 2

Two separate samples are being used to estimate the population mean difference between two treatment conditions.Which of the following would produce the widest confidence interval?

Accepted Answer

A) n1 = n2 = 10 with a pooled variance of 10 
B) n1 = n2 = 10 with a pooled variance of 100 
C) n1 = n2 = 20 with a pooled variance of 10 
D) n1 = n2 = 20 with a pooled variance of 100 
A) n1 = n2 = 10 with a pooled variance of 10 
B) n1 = n2 = 10 with a pooled variance of 100 
C) n1 = n2 = 20 with a pooled variance of 10 
D) n1 = n2 = 20 with a pooled variance of 100 B

Question 3

A researcher reports an independent-measures t statistic with df = 16.How many participants were in the entire study?

Accepted Answer

A) 17 
B) 18 
C) 33 
D) 34 
A) 17 
B) 18 
C) 33 
D) 34 B

Question 4

One sample has n = 5 scores and the second has n = 10 scores.If the pooled variance for the two samples is 30,what is the value of the estimated standard error for the sample mean difference?

Accepted Answer

A) 2 
B) √2 
C) 9 
D) 3 
A) 2 
B) √2 
C) 9 
D) 3

Question 5

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

Question 6

The following data are from an independent-measures experiment comparing two treatment conditio
 $$\begin{array} { c c } 
\text { Treatment 1 } & \text { Treatment 2 } \
\hline 6 & 19 \
13 & 9 \
8 & 18 \
4 & 10 \
13 & 12 \
4 & 14 \
11 & 19 \
5 & 11
\end{array}$$ 
a.Do these data indicate a significant difference between the treatments at the .05 level of significance?
b.Compute r² to measure the size of the treatment effect.
c.Write a sentence demonstrating how the outcome of the hypothesis test and the measure of effect size would appear in a research report.

Accepted Answer

a.For treatment 1,M = 8 and SS = 104.For

Question 7

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 
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 8

What is the average value expected for the independent-measures t statistic if the null hypothesis is true?

Accepted Answer

A) 0 
B) 1 
C) ±1 
D) M1 - M2 
A) 0 
B) 1 
C) ±1 
D) M1 - M2

Question 9

Assuming a 5-point difference between the two sample means,which set of sample characteristics is most likely to produce a significant value for the independent-measures t statistic?

Accepted Answer

A) Large sample sizes and small sample variances 
B) Large sample sizes and large sample variances 
C) Small sample sizes and small sample variances 
D) Small sample sizes and large sample variances 
A) Large sample sizes and small sample variances 
B) Large sample sizes and large sample variances 
C) Small sample sizes and small sample variances 
D) Small sample sizes and large sample variances

Question 10

For an independent-measures t statistic,what is the effect of increasing the number of scores in the samples?

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) Increase the likelihood of rejecting H0 and have little or no effect on measures of effect size 
D) Decrease the likelihood of rejecting H0 and have little or no effect on 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) Increase the likelihood of rejecting H0 and have little or no effect on measures of effect size 
D) Decrease the likelihood of rejecting H0 and have little or no effect on measures of effect size

Question 11

Which of the following sets of data would produce the largest value for an independent-measures t statistic?

Accepted Answer

A) Sample means of 10 and 12, with sample variances of 20 and 25. 
B) Sample means of 10 and 12, with sample variances of 120 and 125. 
C) Sample means of 10 and 20, with sample variances of 20 and 25. 
D) Sample means of 10 and 20, with sample variances of 120 and 125. 
A) Sample means of 10 and 12, with sample variances of 20 and 25. 
B) Sample means of 10 and 12, with sample variances of 120 and 125. 
C) Sample means of 10 and 20, with sample variances of 20 and 25. 
D) Sample means of 10 and 20, with sample variances of 120 and 125.

Question 12

An independent-measures research study with n = 5 participants in each treatment produces sample variances of 8 and 10,and a 2-point difference between the two treatment means.What is the value of Cohen's d?

Accepted Answer

A) 2/2 
B) 2/3 
C) 2/9 
D) 2/18 
A) 2/2 
B) 2/3 
C) 2/9 
D) 2/18

Question 13

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

Question 14

What is the pooled variance for the following two samples?

Accepted Answer

A) 7 	Sample 1: n = 8 and SS = 168 
B) √7 	Sample 2: n = 6 and SS = 120 
C) 20.57 
D) 24 
A) 7 	Sample 1: n = 8 and SS = 168 
B) √7 	Sample 2: n = 6 and SS = 120 
C) 20.57 
D) 24

Question 15

An independent-measures study has M₁ = 49 and M₂ = 45 with an estimated standard error of 4.For this study,Cohen's d = 4/4 = 1.00.

Accepted Answer

A) True 
 B)False

Question 16

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

Question 17

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 18

If other factors are held constant,the larger the values for the two sample variances,the greater the likelihood that the independent-measures t test will find a significant difference.

Accepted Answer

A) True 
 B)False

Question 19

A researcher predicts that scores in treatment A will be higher than scores in treatment B.Which of the following is the correct null hypothesis for a one-tailed test evaluating this prediction?

Accepted Answer

A) µA = µB B) µA / µB C) µA > µB D) µA < µB A) µA = µB B) µA / µB C) µA > µB D) µA < µB

Question 20

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

One sample has s² = 12,and a second sample has s² = 15.The pooled variance for these two samples will be between 12 and 15.

Two separate samples are being used to estimate the population mean difference between two treatment conditions.Which of the following would produce the widest confidence interval?

A researcher reports an independent-measures t statistic with df = 16.How many participants were in the entire study?

One sample has n = 5 scores and the second has n = 10 scores.If the pooled variance for the two samples is 30,what is the value of the estimated standard error for the sample mean difference?

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.

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?

What is the average value expected for the independent-measures t statistic if the null hypothesis is true?

Assuming a 5-point difference between the two sample means,which set of sample characteristics is most likely to produce a significant value for the independent-measures t statistic?

For an independent-measures t statistic,what is the effect of increasing the number of scores in the samples?

Which of the following sets of data would produce the largest value for an independent-measures t statistic?

An independent-measures research study with n = 5 participants in each treatment produces sample variances of 8 and 10,and a 2-point difference between the two treatment means.What is the value of Cohen's d?

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

What is the pooled variance for the following two samples?

An independent-measures study has M₁ = 49 and M₂ = 45 with an estimated standard error of 4.For this study,Cohen's d = 4/4 = 1.00.

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?

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

If other factors are held constant,the larger the values for the two sample variances,the greater the likelihood that the independent-measures t test will find a significant difference.

A researcher predicts that scores in treatment A will be higher than scores in treatment B.Which of the following is the correct null hypothesis for a one-tailed test evaluating this prediction?

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?

Introduction to Statistics.

Frequency Distributions.

Central Tendency.

Variability.

z-Scores: Location of Scores and Standardized Distributions.

Probability.

Probability and Samples: 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 and Two-Factor Analysis of Variance

Correlation and Regression.

The Chi-Square Statistic: Tests for Goodness of Fit and Independence

Filters

Exam 10: The t Test for Two Independent Samples

One sample has s² = 12,and a second sample has s² = 15.The pooled variance for these two samples will be between 12 and 15.

Two separate samples are being used to estimate the population mean difference between two treatment conditions.Which of the following would produce the widest confidence interval?

A researcher reports an independent-measures t statistic with df = 16.How many participants were in the entire study?

One sample has n = 5 scores and the second has n = 10 scores.If the pooled variance for the two samples is 30,what is the value of the estimated standard error for the sample mean difference?

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.

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?

What is the average value expected for the independent-measures t statistic if the null hypothesis is true?

Assuming a 5-point difference between the two sample means,which set of sample characteristics is most likely to produce a significant value for the independent-measures t statistic?

For an independent-measures t statistic,what is the effect of increasing the number of scores in the samples?

Which of the following sets of data would produce the largest value for an independent-measures t statistic?

An independent-measures research study with n = 5 participants in each treatment produces sample variances of 8 and 10,and a 2-point difference between the two treatment means.What is the value of Cohen's d?

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

What is the pooled variance for the following two samples?

An independent-measures study has M₁ = 49 and M₂ = 45 with an estimated standard error of 4.For this study,Cohen's d = 4/4 = 1.00.

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?

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

If other factors are held constant,the larger the values for the two sample variances,the greater the likelihood that the independent-measures t test will find a significant difference.

A researcher predicts that scores in treatment A will be higher than scores in treatment B.Which of the following is the correct null hypothesis for a one-tailed test evaluating this prediction?

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?

Introduction to Statistics.

Frequency Distributions.

Central Tendency.

Variability.

z-Scores: Location of Scores and Standardized Distributions.

Probability.

Probability and Samples: 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 and Two-Factor Analysis of Variance

Correlation and Regression.

The Chi-Square Statistic: Tests for Goodness of Fit and Independence

Filters