Deck 11: Two-Sample T-Test: Related Samples Design

Question 1

A repeated measures study involves

A) two sets of scores from the same subjects.
B) two sets of scores from two different samples.
C) replicating a study to see if similar results are obtained.
D) participants doing the same task repeatedly.

Answer 1

A

Question 2

A repeated measures study is

A) also called a within-subjects design.
B) also called a between-subjects design.
C) a type of related samples design.
D) both "a" and "c" are correct.

Answer 2

D

Question 3

The standard deviation for a two-sample, repeated measures t test is called the

A) standard error of the mean.
B) standard error of the mean difference.
C) standard error of the difference between means.
D) standard error of the deviation of means.

Answer 3

B

Question 4

The symbol for the standard error value for a repeated measures t test is

A) s
B) s_M
C)
D) s_M₁-M₂

Question 5

If the sum of the difference scores in a repeated measures t test is 68 and n = 16, what is the mean difference value?

A) 4.25
B) 4.53
C) 17
D) 23

Question 6

Given difference values of 21, -6, 17, -10, and 13, what is M_D?

A) 35
B) 7
C) 8.75
D) 15.63

Question 7

Which of the following will give you M_D

A) ∑D
B) ∑D²
C) ∑D/n
D) ∑D²/n

Question 8

In a repeated measures t test, difference values are determined by

A) subtracting post-test scores from pre-test scores.
B) subtracting pre-test scores from post-test scores.
C) squaring the post-test scores.
D) squaring the pre-test scores.

Question 9

Which of the following is the working formula for the repeated measures t test?

A)
B)
C)
D)

Question 10

Which is the correct df for a related samples t test?

A) n - 1
B) n₁ + n₂ - 2
C) n₁ - n₂ + 2
D) n + 1

Question 11

A repeated measures t test was conducted using a sample size of n = 28. What is the df?

A) 26
B) 27
C) 54
D) 30

Question 12

If df = 34 for a repeated measures t test, how many subjects participated in the study?

A) 17
B) 16
C) 35
D) 36

Question 13

For a repeated measures t test, the null hypothesis attributes

A) mean differences between pre- and post-test scores to random sampling error.
B) any differences between the means for group 1 and group 2 to random sampling error.
C) mean differences between pre- and post-test scores to the effects of an independent variable.
D) any differences between the means for group 1 and group 2 to the effects of an independent variable.

Question 14

For a repeated measures t test, the alternative hypothesis attributes

A) mean differences between pre- and post-test scores to random sampling error.
B) any differences between the means for group 1 and group 2 to random sampling error.
C) mean differences between pre- and post-test scores to the effects of an independent variable.
D) any differences between the means for group 1 and group 2 to the effects of an independent variable.

Question 15

Which of the following is the correct notation for the nondirectional alternative hypothesis of a repeated measures t test?

A) H₁: μ_D ≠ 0
B) H₁: μ_D > 0
C) H₁: μ_D < 0
D) either "b" or "c" above

Question 16

Which of the following is the correct notation for the null hypothesis of a repeated measures t test for which the alternative hypothesis is nondirectional?

A) H₀: μ₁ = μ₂
B) H₀: μ_D = 0
C) H₀: μ₁ - μ₂ = 0
D) H₀: either "a" or "c" above

Question 17

Which of the following is a directional alternative hypothesis for a repeated measures t test?

A) H₁: μ₁ ≥ μ₂
B) H₁: μ₁ > <μ₂
C) H₁: μ_D ≤ 0
D) H₁: μ_D < 0

Question 18

Which of the following is a directional null hypothesis for a repeated measures t test?

A) H₀: μ_D < 0
B) H₀: μ_D ≥ 0
C) H₀: μ₁ > μ₂
D) H₀: μ₁ ≤ μ₂

Question 19

Given an alpha level of .01 and n = 22, what would t_crit be for a nondirectional repeated measures t test?

A) -2.518
B) +2.518
C) ±2.831
D) either "a" or "b" above

Question 20

Given an alpha level of .05 and n = 18, what would t_crit be for a nondirectional repeated measures test?

A) ±1.746
B) ±2.120
C) ±1.740
D) ±2.110

Question 21

Which of the following is one of the procedures involved in conducting a repeated measures t test?

A) Each set of scores will be squared.
B) The pre-test scores are subtracted from the post-test scores.
C) Each set of scores will be added; the total of each will then be divided by n to arrive at a mean for each group.
D) The mean difference value is determined by dividing ∑D² by n.

Question 22

Which of the following terms is eliminated from the original formula for the related samples t test?

A) μ_D
B) M_D
C)
D)

Question 23

Given: ∑D = 32, n = 8, and s_D = 5, what is Cohen's d?

A) 4
B) .8
C) 6.4
D) .4

Question 24

Given ∑D = 64, n = 9, and s_D = 8, what is ?

A) 8
B) 7.11
C) 2.67
D) .88

Question 25

Given ∑D = 224, n = 16, and s_D = 11, what is t_obt?

A) 14
B) 1.45
C) 5.09
D) 16

Question 26

Given SS_D = 408, M_D = 8, and n = 9, what is ?

A) 2.38
B) 51
C) 45.33
D) 2.67

Question 27

Which is the correct Cohen d formula for a repeated measures t test?

A)
B)
C)
D)

Question 28

Which of the assumptions below does not apply to a repeated measures t test?

A) independent and random sampling
B) normal distribution of the dependent variable
C) measurement of the dependent variable on interval or ratio scales
D) homogeneity of variance

Question 29

Which of the following is NOT one of the advantages of a repeated measures t test?

A) the measurement of developmental changes
B) fewer subjects
C) order effects
D) less variability

Question 30

One of the disadvantages of the repeated measures design is

A) order effects.
B) the greater number of subjects required.
C) more sampling error.
D) greater variability due to individual differences.

Question 31

If you wanted to measure developmental changes over time, which t test(s) would be most suitable?

A) one-sample t test
B) two-sample t test, independent samples design
C) two-sample t test, repeated measures design
D) either "b" or "c" above

Question 32

Which type of study uses the same subjects on more than one occasion?

A) z-test
B) t test, independent samples design
C) t test, repeated measures design
D) one-sample t test

Question 33

Problems that could arise related to the order in which the independent variable was presented include all of the following, except

A) boredom.
B) lingering effects of a medication.
C) improved performance due to practice.
D) counterbalancing.

Question 34

To control for some of the problems associated with order effects in a repeated measures t test, you could

A) shorten the length of time between conditions.
B) use counterbalancing.
C) allow subjects to take a nap between treatment conditions.
D) use different subjects for the second condition.

Question 35

If a researcher exposes half of the subjects in an experiment to condition A and then B, and the other half of the subjects to condition B first and then A, what procedure has been used?

A) counterbalancing
B) order effects
C) switchback
D) reversal

Question 36

In a repeated measures t test,

A) one group of subjects is exposed to one treatment condition.
B) different subjects are exposed to different treatments.
C) more than one dependent variable is being measured.
D) the same subjects are measured before and after a treatment intervention.

Question 37

One study involved one group with n = 16 and M = 48 and another group with n = 18 and M = 62. Which of the following statistical tests would be appropriate for the analysis?

A) one-sample t test
B) two-sample t test, independent samples design
C) two-sample t test, repeated measures design
D) either "b" or "c" above

Question 38

The emergence of self-recognition is sometimes studied using the red dot test in which a red dot is placed on a child's forehead or nose. The child is then placed in front of a mirror. If the child touches his or her nose rather than pointing at the mirror or looking behind it for someone, then self-recognition is inferred. A developmental psychologist conducts the red dot test by using a sample of 15 one-month-old babies. She tests them again at 18 months of age. What type of test was employed?

A) z-test
B) one-sample t test
C) independent samples t test
D) repeated measures t test

Question 39

The emergence of self-recognition is sometimes studied using the red dot test in which a red dot is placed on a child's forehead or nose. The child is then placed in front of a mirror. If the child touches his or her nose rather than pointing at the mirror or looking behind it for someone, then self-recognition is inferred. A developmental psychologist conducts the red dot test by using a sample of 15 one-month-old babies and another sample of 18 month-old babies. What type of test was employed?

A) z-test
B) one-sample t test
C) independent samples t test
D) repeated measures t test

Question 40

A researcher studying the psychological effects of color measures the blood pressure of a sample of 16 subjects while sitting in an all blue room. She then moves them to an all yellow room and takes their blood pressure again. What type of test was employed?

A) z-test
B) one-sample t test
C) independent samples t test
D) repeated measures t test

Question 41

What is a repeated measures study?

Question 42

What is the sampling distribution called for a t test with a repeated measures design?

Question 43

What is the standard deviation called for a t test with a repeated measures design?

Question 44

What are the assumptions for a two-sample t test, repeated measures design?

Question 45

What are the advantages of using a repeated measures t test rather than an independent samples t test?

Question 46

What are the disadvantages of using a repeated measures t test?

Question 47

What is meant by counterbalancing?

Question 48

For the items below, indicate what type of t test is called for: a one-sample t test, an independent samples t test, or a repeated measures t test.
a. Motivation scores are measured for a sample of students before and after Spring Break.
b. University freshmen in the state of Minnesota have a mean score of 65 on a math test. A teacher has developed a new technique for teaching math and a sample of high school graduates completes the program over the summer. Before beginning their university studies, they are administered the math test to see if students who completed the program score higher than the state average.
c. The average number of times that females contribute to class discussions over the course of a semester is compared to the average number of times that males contribute.
d. The national average on a measure of Need for Achievement is 50. An Olympic coach believes that athletes training for the Olympics would score higher on this trait and so she administers the test to her trainees to compare.
e. A psychologist used the smile/frown technique to study the facial feedback hypothesis which proposes that feedback from the skeletal muscles in our face influences our emotional experience. The psychologist asked one group to rate the funniness of a packet of cartoons while holding a pencil between their teeth without touching their lips (as if to smile). Another group rated the same packet of cartoons while holding the pencil between their lips without touching their teeth (as if to frown).
f. An optimism test is given to military personnel upon their enlistment and then again at the end of their military service.

Question 49

For the summary values that follow for a repeated measures t test, calculate: ∑D = -21, ∑D² = 171, n = 6

Question 50

Given the summary values that follow for a repeated measures t test, calculate t_obt: ∑D = 31, ∑D² = 331, n = 10.

Question 51

For the scores that follow, conduct a two-tailed, repeated measures test using α = .05.

Question 52

Professors who teach introductory psychology courses often hear students say that psychology is just "common sense." To test this assumption, Professor Empiricism administers a Fact or Fiction Survey at the beginning of the semester and then again at the end of the semester. She believes that after students are exposed to research-based evidence, students will score higher on the end-of-semester survey. Pre- and post-scores for a sample of her students are listed below:
a. Test the professor's hypothesis using a one-tailed, repeated measures t test with α = .05.
b. Calculate Cohen's d effect size and interpret the result.