Question 1

Which of the following is a nondirectional alternative hypothesis for an independent samples t test?

Accepted Answer

A)  H₁: μ₁ = μ₂ 
B)  H₁: μ₁ > μ₂ 
C)  H₁: μ₁ ≠ μ₂ 
D)  H₁: μ₁ ≥ μ₂ 
A)  H₁: μ₁ = μ₂ 
B)  H₁: μ₁ > μ₂ 
C)  H₁: μ₁ ≠ μ₂ 
D)  H₁: μ₁ ≥ μ₂ C

Question 2

Which of the following is not one of the assumptions of the independent samples t test?

Accepted Answer

A)  Independent and random selection of subjects. 
B)  The dependent variable can be measured on an interval or ratio scale. 
C)  The dependent variable is normally distributed in the population. 
D)  Homogeneity of variance of the independent variable in the population of interest. 
A)  Independent and random selection of subjects. 
B)  The dependent variable can be measured on an interval or ratio scale. 
C)  The dependent variable is normally distributed in the population. 
D)  Homogeneity of variance of the independent variable in the population of interest. D

Question 3

If the null hypothesis is H₀: μ₁ ≤ μ₂, then the alternative hypothesis would be _____________.

Accepted Answer

A)  H₁: μ₁ > μ₂ 
B)  H₁: μ₁ ≥ μ₂ 
C)  H₁: μ₁ = μ₂ 
D)  H₁: μ₁ ≠ μ₂ 
A)  H₁: μ₁ > μ₂ 
B)  H₁: μ₁ ≥ μ₂ 
C)  H₁: μ₁ = μ₂ 
D)  H₁: μ₁ ≠ μ₂ A

Question 4

Using the summary values that follow, conduct a two-tailed independent samples t test with α = .01:

Accepted Answer

Step 1:
H₀: μ₁ = μ₂
H₁:μ₁ ≠ μ₂

Question 5

represents

Accepted Answer

A)  the standard error value for a repeated measures t test. 
B)  the variance values for an independent samples t test. 
C)  the standard error value for an independent samples t test. 
D)  the effect size for an independent samples t test. 
A)  the standard error value for a repeated measures t test. 
B)  the variance values for an independent samples t test. 
C)  the standard error value for an independent samples t test. 
D)  the effect size for an independent samples t test.

Question 6

The following results were reported for an independent samples t test: t(18) = +2.15, p < .05. The results suggest that

Accepted Answer

A)  H₀ should be rejected. 
B)  H₀ should fail to be rejected. 
C)  the results are unlikely if H₀ is true. 
D)  both "a" and "c" above. 
A)  H₀ should be rejected. 
B)  H₀ should fail to be rejected. 
C)  the results are unlikely if H₀ is true. 
D)  both "a" and "c" above.

Question 7

A medical researcher is studying a new drug which she believes will decrease outbreaks in people who suffer from acne. She obtains two samples of acne sufferers. Group one, consisting of 8 individuals, applies a daily facial cream which contains the active ingredient. Group two, consisting of 6 individuals, applies the same facial cream except that it does not contain the active ingredient.
a. Write the symbolic notation for the null and alternative hypotheses.
b. If tobt = -2.84 and α = .01, was there a significant effect? How do you know?

Accepted Answer

Acne sufferers
a. H₀: μ₁ ≥ μ₂ 
H₁: μ₁ <

Question 8

A nondirectional alternative hypothesis for an independent samples t test states that

Accepted Answer

A)  there is no significant difference between means. 
B)  one mean will be higher or lower than the other mean. 
C)  a difference between means is due to chance. 
D)  a difference between means is due to treatment. 
A)  there is no significant difference between means. 
B)  one mean will be higher or lower than the other mean. 
C)  a difference between means is due to chance. 
D)  a difference between means is due to treatment.

Question 9

The following results were reported for an independent samples t test: t(21) = -2.32, p > .01. The results suggest that

Accepted Answer

A)  H₀ should be rejected. 
B)  H₀ should fail to be rejected. 
C)  the results are unlikely if H₀ is true. 
D)  both "a" and "c" above. 
A)  H₀ should be rejected. 
B)  H₀ should fail to be rejected. 
C)  the results are unlikely if H₀ is true. 
D)  both "a" and "c" above.

Question 10

A t test that involves an independent samples design is also called a

Accepted Answer

A)  within-samples design. 
B)  repeated measures design. 
C)  related-subjects design. 
D)  between-subjects design. 
A)  within-samples design. 
B)  repeated measures design. 
C)  related-subjects design. 
D)  between-subjects design.

Question 11

The results section of an independent samples t test includes the statement "t(33) = -2.14." What was the total number of participants in the study?

Accepted Answer

A)  34 
B)  32 
C)  35 
D)  31 
A)  34 
B)  32 
C)  35 
D)  31

Question 12

In a two-tailed independent samples t test, the null hypothesis specifies the difference between means values to be ________.

Accepted Answer

A)  0 
B)  1 
C)  .01 
D)  .05 
A)  0 
B)  1 
C)  .01 
D)  .05

Question 13

For an independent samples t test, the ________ the difference between the sample means, the ________ the likelihood of rejecting H₀.

Accepted Answer

A)  smaller; greater 
B)  smaller; less 
C)  larger; greater 
D)  larger; less 
A)  smaller; greater 
B)  smaller; less 
C)  larger; greater 
D)  larger; less

Question 14

If our obtained t-value for an independent samples t test is -2.21 and we are using a nondirectional alternative hypothesis, which of the following tcrit value(s) will lead to the rejection of H₀?

Accepted Answer

A)  +2.18 
B)  -2.03 
C)  -2.41 
D)  either "a" or "b" above 
A)  +2.18 
B)  -2.03 
C)  -2.41 
D)  either "a" or "b" above

Question 15

The mean stubbornness scores for the 8 individuals in sample A was 36. The mean for sample B, consisting of 12 individuals, was 42. A two-tailed independent samples t test was conducted and tobt = +2.33. Given an α = .05, we can 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 16

If α = .05 and p < .05 for a two-tailed independent samples t test, the result suggests that

Accepted Answer

A)  there was no difference between means. 
B)  we should fail to reject H₀. 
C)  there was a significant difference between means. 
D)  both "a" and "b" are correct. 
A)  there was no difference between means. 
B)  we should fail to reject H₀. 
C)  there was a significant difference between means. 
D)  both "a" and "b" are correct.

Question 17

Define homogeneity of variance.

Accepted Answer

Homogeneity of variance means

Question 18

Given the summary data that follow, calculate tobt:

Accepted Answer

Question 19

The sample sizes for an independent samples t test are n₁ = 24 and n₂ = 18. What df value should be used?

Accepted Answer

A)  42 
B)  41 
C)  40 
D)  39 
A)  42 
B)  41 
C)  40 
D)  39

Question 20

Using symbolic notation, write the null and alternative hypotheses for a one-tailed independent samples t test for which the researcher expects the scores in condition one to be lower than the scores in condition two.

Accepted Answer

H₀: μ₁ ≥ μ

Which of the following is a nondirectional alternative hypothesis for an independent samples t test?

Which of the following is not one of the assumptions of the independent samples t test?

If the null hypothesis is H₀: μ₁ ≤ μ₂, then the alternative hypothesis would be _____________.

Using the summary values that follow, conduct a two-tailed independent samples t test with α = .01:

represents

The following results were reported for an independent samples t test: t(18) = +2.15, p < .05. The results suggest that

A nondirectional alternative hypothesis for an independent samples t test states that

The following results were reported for an independent samples t test: t(21) = -2.32, p > .01. The results suggest that

A t test that involves an independent samples design is also called a

The results section of an independent samples t test includes the statement "t(33) = -2.14." What was the total number of participants in the study?

In a two-tailed independent samples t test, the null hypothesis specifies the difference between means values to be ________.

For an independent samples t test, the the difference between the sample means, the the likelihood of rejecting H₀.

If our obtained t-value for an independent samples t test is -2.21 and we are using a nondirectional alternative hypothesis, which of the following t_crit value(s) will lead to the rejection of H₀?

The mean stubbornness scores for the 8 individuals in sample A was 36. The mean for sample B, consisting of 12 individuals, was 42. A two-tailed independent samples t test was conducted and t_obt = +2.33. Given an α = .05, we can conclude that

If α = .05 and p < .05 for a two-tailed independent samples t test, the result suggests that

Define homogeneity of variance.

Given the summary data that follow, calculate t_obt:

The sample sizes for an independent samples t test are n₁ = 24 and n₂ = 18. What df value should be used?

Using symbolic notation, write the null and alternative hypotheses for a one-tailed independent samples t test for which the researcher expects the scores in condition one to be lower than the scores in condition two.

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

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

Which of the following is a nondirectional alternative hypothesis for an independent samples t test?

Which of the following is not one of the assumptions of the independent samples t test?

If the null hypothesis is H₀: μ₁ ≤ μ₂, then the alternative hypothesis would be _____________.

Using the summary values that follow, conduct a two-tailed independent samples t test with α = .01:

represents

The following results were reported for an independent samples t test: t(18) = +2.15, p < .05. The results suggest that

A nondirectional alternative hypothesis for an independent samples t test states that

The following results were reported for an independent samples t test: t(21) = -2.32, p > .01. The results suggest that

A t test that involves an independent samples design is also called a

The results section of an independent samples t test includes the statement "t(33) = -2.14." What was the total number of participants in the study?

In a two-tailed independent samples t test, the null hypothesis specifies the difference between means values to be ________.

For an independent samples t test, the ________ the difference between the sample means, the ________ the likelihood of rejecting H₀.

If our obtained t-value for an independent samples t test is -2.21 and we are using a nondirectional alternative hypothesis, which of the following tcrit value(s) will lead to the rejection of H₀?

The mean stubbornness scores for the 8 individuals in sample A was 36. The mean for sample B, consisting of 12 individuals, was 42. A two-tailed independent samples t test was conducted and tobt = +2.33. Given an α = .05, we can conclude that

If α = .05 and p < .05 for a two-tailed independent samples t test, the result suggests that

Define homogeneity of variance.

Given the summary data that follow, calculate tobt:

The sample sizes for an independent samples t test are n₁ = 24 and n₂ = 18. What df value should be used?

Using symbolic notation, write the null and alternative hypotheses for a one-tailed independent samples t test for which the researcher expects the scores in condition one to be lower than the scores in condition two.

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

For an independent samples t test, the the difference between the sample means, the the likelihood of rejecting H₀.

If our obtained t-value for an independent samples t test is -2.21 and we are using a nondirectional alternative hypothesis, which of the following t_crit value(s) will lead to the rejection of H₀?

The mean stubbornness scores for the 8 individuals in sample A was 36. The mean for sample B, consisting of 12 individuals, was 42. A two-tailed independent samples t test was conducted and t_obt = +2.33. Given an α = .05, we can conclude that

Given the summary data that follow, calculate t_obt: