Question 1

The homogeneity of variance assumption for the independent samples t test requires that

Accepted Answer

A)  the population variances of the dependent variable be approximately equal. 
B)  the population variances of the independent variable be approximately equal. 
C)  the sample sizes for the two groups be equal. 
D)  the dependent variable be normally distributed in the population. 
A)  the population variances of the dependent variable be approximately equal. 
B)  the population variances of the independent variable be approximately equal. 
C)  the sample sizes for the two groups be equal. 
D)  the dependent variable be normally distributed in the population.

Question 2

Explain the difference between a one-sample t test and an independent samples t test.

Accepted Answer

A one-sample t test involves assessing a

Question 3

A two-tailed independent samples t test was conducted with an α = .01. The mean for group A, consisting of 8 individuals, was 63. The mean for group B, consisting of 9 individuals, was 61. If the obtained t-value was -2.63, we could conclude that

Accepted Answer

A)  there was no significant difference between the means. 
B)  there was a significant difference between the means. 
C)  the null hypothesis should be rejected. 
D)  both "b" and "c" are correct. 
A)  there was no significant difference between the means. 
B)  there was a significant difference between the means. 
C)  the null hypothesis should be rejected. 
D)  both "b" and "c" are correct.

Question 4

List the assumptions of an independent samples t test.

Accepted Answer

Assumptions of an independent samples t

Question 5

Using the summary values that follow, conduct a one-tailed, independent samples t test with α = .05: M₁ = 22, n₁ = 8, M₂ = 25, n₂ = 9,   Assume that the researcher expects scores in condition one to be lower than the scores in condition two.

Accepted Answer

Step 1:
H₀: μ₁ ≥ μ₂
H₁: μ₁ < μ₂
Step 2:

Question 6

A sleep researcher is studying the effect of sleep deprivation on cognitive abilities. In his most recent study, one group of participants was kept awake all night and another group was allowed to sleep comfortably. Both groups were subsequently given a basic math test to see how many problems could be solved within a 5-minute period of time. Scores for both groups are listed below. The researcher believes that the sleep deprived participants will solve fewer problems
.
   a. Conduct an independent samples t test with α = .01.
b. Determine and interpret the effect size.

Accepted Answer

Step 1:
H₀: μ₁ ≥ μ₂
H₁ μ₁ < μ₂
Step 2:
α

Question 7

A psychologist has developed a workshop designed to increase the degree of optimism that people experience. She conducts a one-tailed independent samples t test with an α = .01 to determine if the workshop in fact improves optimism scores. Group A, consisting of 16 individuals, participated in the workshop and subsequently obtained a M₁ = 92 on an optimism assessment. Group B, consisting of 13 individuals, takes the assessment without attending the workshop and obtained a M₂ = 88. If the obtained t-value was +2.33, we could conclude that

Accepted Answer

A)  the group that attended the workshop scored significantly higher on optimism than the group that didn't attend. 
B)  the group that attended the workshop scored higher than the group that didn't attend, but the difference between the means was not significant. 
C)  the null hypothesis should be rejected. 
D)  Both "a" and "c" above are correct. 
A)  the group that attended the workshop scored significantly higher on optimism than the group that didn't attend. 
B)  the group that attended the workshop scored higher than the group that didn't attend, but the difference between the means was not significant. 
C)  the null hypothesis should be rejected. 
D)  Both "a" and "c" above are correct.

Question 8

If df = 42, then the total number of participants in an independent samples t test was ________.

Accepted Answer

A)  43 
B)  41 
C)  40 
D)  44 
A)  43 
B)  41 
C)  40 
D)  44

Question 9

Given the summary data that follow, calculate the standard error of difference between means: SS₁ = 289, n₁ = 12, SS₂ = 315, n₂ = 15.

Accepted Answer

The answer of Given the summary data that follow, calculate...

Question 10

The difference between means is 4. The pooled variance is 9. What is the value of Cohen's d for an independent samples t test?

Accepted Answer

A)  2.25 
B)  .44 
C)  .75 
D)  1.33 
A)  2.25 
B)  .44 
C)  .75 
D)  1.33

The homogeneity of variance assumption for the independent samples t test requires that

Explain the difference between a one-sample t test and an independent samples t test.

A two-tailed independent samples t test was conducted with an α = .01. The mean for group A, consisting of 8 individuals, was 63. The mean for group B, consisting of 9 individuals, was 61. If the obtained t-value was -2.63, we could conclude that

List the assumptions of an independent samples t test.

Using the summary values that follow, conduct a one-tailed, independent samples t test with α = .05: M₁ = 22, n₁ = 8, M₂ = 25, n₂ = 9, Assume that the researcher expects scores in condition one to be lower than the scores in condition two.

If df = 42, then the total number of participants in an independent samples t test was ________.

Given the summary data that follow, calculate the standard error of difference between means: SS₁ = 289, n₁ = 12, SS₂ = 315, n₂ = 15.

The difference between means is 4. The pooled variance is 9. What is the value of Cohen's d for an independent samples t test?

Organizing Data Using Tables and Graphs

Measures of Central Tendency

Measures of Variability

Z-Scores and Other Standard Scores

Probability and the Normal Distribution

Sampling Distribution of Means

Hypothesis Testing

One-Sample T-Test

Two-Sample T-Test: Related Samples Design

Confidence Interval Versus Point Estimation

One-Way Analysis of Variance

Factorial Analysis of Variance

Correlation and Regression

Chi-Square

Introduction to Statistics

Nonparametric Statistics for Ordinal Data

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Exam 10: Two-Sample T-Test: Independent Samples Design

The homogeneity of variance assumption for the independent samples t test requires that

Explain the difference between a one-sample t test and an independent samples t test.

A two-tailed independent samples t test was conducted with an α = .01. The mean for group A, consisting of 8 individuals, was 63. The mean for group B, consisting of 9 individuals, was 61. If the obtained t-value was -2.63, we could conclude that

List the assumptions of an independent samples t test.

Using the summary values that follow, conduct a one-tailed, independent samples t test with α = .05: M₁ = 22, n₁ = 8, M₂ = 25, n₂ = 9, Assume that the researcher expects scores in condition one to be lower than the scores in condition two.

If df = 42, then the total number of participants in an independent samples t test was ________.

Given the summary data that follow, calculate the standard error of difference between means: SS₁ = 289, n₁ = 12, SS₂ = 315, n₂ = 15.

The difference between means is 4. The pooled variance is 9. What is the value of Cohen's d for an independent samples t test?

Organizing Data Using Tables and Graphs

Measures of Central Tendency

Measures of Variability

Z-Scores and Other Standard Scores

Probability and the Normal Distribution

Sampling Distribution of Means

Hypothesis Testing

One-Sample T-Test

Two-Sample T-Test: Related Samples Design

Confidence Interval Versus Point Estimation

One-Way Analysis of Variance

Factorial Analysis of Variance

Correlation and Regression

Chi-Square

Introduction to Statistics

Nonparametric Statistics for Ordinal Data

Filters