1. ( FILL IN BLANK)

For the following problem, please round to two decimal places:

An experimenter hypothesizes that biology majors score higher than literature majors on an intelligence test. If the mean score for biology majors is 27.7 and the mean score for literature majors is 25.2 , and the S_Diff.is 3.2, the t score is: ______________

2.

For the following problem, please round to two decimal places:

A social psychologist interested in cultural differences compared women of two ethnic groups on a Role Approval Index on which high scores indicated high degrees of approval of one's own social role. The results were as follows. Ethnic Group A: N₁ = 13, M₁ = 59, S₁ = 4.8; Ethnic Group B: N₂ = 16, M₂ = 52, S₂ = 4.1. What is S²_Pooled?

3.

A professor is interested in how a new kind of study guide would affect exam scores. In her class of 20 students, she gives 10 randomly selected students the new study and the remaining 10 students the old study guide for an upcoming exam. She then conducts a t test for independent means on their exam scores. What is the null hypothesis?

Group of answer choices

The students with the old study guide will perform worse on the exam

The students with the old study guide will perform better on the exam

The students with the new study guide will perform better on the exam

There will be no difference in the exam performances of the two groups

4.

For the following problem, please round to two decimal places:

A social psychologist interested in cultural differences compared women of two ethnic groups on a Role Approval Index on which high scores indicated high degrees of approval of one's own social role. The results were as follows. Ethnic Group A: N₁ = 10, M₁ = 55, S₁ = 4.9; Ethnic Group B: N₂ = 19, M₂ = 52, S₂ = 4.5. If a t test for independent means is conducted, how many degrees of freedom will be used to locate the cutoff score(s) in the t table?

5.

Which of the following is true when carrying out a t test for independent means? You may select more than one answer.

Group of answer choices

There are two scores per participant

Two independent groups are being compared

The mean (M) in the formula for calculating t is replaced with the difference between the means (M₁-M₂)

The population variances are known

6.

In which of the following situations would a t test for independent means be conducted?

Group of answer choices

A comparison of the test scores from a group of students that has completed a special summer program designed to boost vocabulary to the test scores of the population of students in general

A comparison of the test scores from a group of students that has studied for a test using university tutoring services and the test scores from the same group of students from before they began studying

A comparison of the musical ability test scores from a group of students that has been taught with a new style of teaching and the music ability scores of another group that has been taught with the old style of teaching

A comparison of a group of participants' pre-test and post-test scores from before and after their completion of a training program intended to increase their memory

7.

The formula for the pooled variance that is used when calculating S_Diff. combines the variance estimates from the two samples in such a way as to give more influence to the variance based on ______ participants

Group of answer choices

the smaller number of

the larger number of

8.

Which of the following is the incorrect way for a t test for independent means to be reported in a research article?

Group of answer choices

independent t(37): 5.7, p: significant

t(37) = 5.7, p = .002

9.

When carrying out a t test for independent means:

Group of answer choices

only the .10 significance level should be used because of the assumption that the variances of the two distributions should be equal

the null hypothesis is rejected if the calculated (obtained) t score is more extreme than the cutoff t score

the medians of the two populations are assumed to be equal

only the .01 significance level should be used because of the greater power compared to a t test for dependent means

10.

Which of the following is not part of conducting a t test for independent means?

Group of answer choices

the pooled estimate of the population variance is figured

the standard deviation of the "distribution of differences between means" is figured

a comparison is made against a Z distribution

the variance of the "distribution of differences between means" is figured

11.

For the following problem, please round to two decimal places:

A social psychologist interested in cultural differences compared women of two ethnic groups on a Role Approval Index on which high scores indicated high degrees of approval of one's own social role. The results were as follows. Ethnic Group A: N₁ = 15, M₁ = 56; Ethnic Group B: N₂ = 16, M₂ = 51

If the standard deviation of the "distribution of the difference between means" is 1.3, what is the t score?

12.

For two sample t test, the mean of the "distribution of differences between means" when the null hypothesis is true is greater than 1.

Group of answer choices

True

False

13.

S²_Pooled is the _____________ and S²_Differenceis the _____________.

Group of answer choices

Standard deviation of the distribution of differences between means; variance of each distribution of means

Variance of each distribution of means; standard deviation of the distribution of differences between means

Weighted average of the estimates of the population variances; Variance of the distribution of differences between means

Standard deviation of the distribution of the distribution of differences between means; weighted average of the estimates of the population variances

14.

Which of the following statements is false? You can select more than one answer.

Group of answer choices

The t-test for independent samples compares a sample's mean to the population mean

The distribution of differences between means is not the comparison distribution when conducting a t test for independent means

The t-test for independent samples compares two samples that are related in some way

15.

If a study measures two groups on each of 100 variables, and the experimenter carries out a t test for independent means for each variable (that is, 100 t tests) using the .01 significance level, how many of those tests would be expected to give statistically significant results?

Group of answer choices

1

10

0

100