Deck 7: Two-Sample T-Test

Question 1

What is the critical t-ratio value for a two-tailed test associated with an extremely large sample size at a 95% confidence level?

A) 2.58
B) 1.96
C) 1.65
D) Need more information

Answer 1

B

Question 2

Which of the following t-ratios could not possibly be statistically significant at the 99% confidence level?

A) 3.00
B) 2.80
C) 2.60
D) 2.50

Answer 2

D

Question 3

Under what condition are the independent and dependent t-tests identical?

A) When the correlation between the two sets of scores is 1.0
B) When the correlation between the two sets of scores is -1.0
C) When the correlation between the two sets of scores is 0
D) Never

Answer 3

C

Question 4

Which of the following terms is NOT associated with a DEPENDENT t-test?

A) Between-subjects comparison
B) Matched subjects
C) Repeated measures
D) Within-subjects comparison

Question 5

Which of the following terms is associated with an INDEPENDENT t-test?

A) Within-subjects comparison
B) Matched subjects
C) Repeated measures
D) Between-subjects comparison

Question 6

Results are said to be statistically significant when the probability that the differences between means is attributable to chance is which of the following?

A) High
B) Low
C) Zero
D) None of the above

Question 7

What does it mean when the null hypothesis is rejected?

A) The two groups are proven to be different.
B) Differences between means are truly different.
C) Observed mean differences are attributable to chance.
D) The probability that the null hypothesis is true is small.

Question 8

In a pre-post design with 10 subjects, which t-test should be used, and what are the degrees of freedom?

A) Independent (t-test) 18 (df)
B) Independent (t-test) 9 (df)
C) Dependent (t-test) 18 (df)
D) Dependent (t-test) 9 (df)

Question 9

What are the degrees of freedom in an independent t-test when 40 people are in each of the treatment and control groups?

A) 39
B) 40
C) 78
D) 80

Question 10

What happens to the t-ratio as the difference between compared means increases?

A) It increases
B) It decreases
C) It depends on the sample sizes
D) It depends on the degrees of freedom

Question 11

What happens to the t-ratio as the difference between compared means decreases?

A) It increases
B) It decreases
C) It depends on the sample sizes
D) It depends on the degrees of freedom

Question 12

What happens to the critical t-ratio as the sample size increases?

A) It increases
B) It decreases
C) It depends on the size of the differences between means
D) None of the above is accurate

Question 13

What happens to the calculated t-ratio as the sample size increases?

A) It increases
B) It decreases
C) It depends on the size of the differences between means
D) None of the above is accurate

Question 14

Which of the following is true for a given level of confidence?

A) As sample size increases, the value of the critical t-ratio decreases.
B) As degrees of freedom increase, the value of the critical t-ratio decreases.
C) Both A and B are correct.
D) Neither A nor B is correct.

Question 15

There are 30 subjects in each of the treatment and control groups. Which type of t-test should be conducted?

A) Dependent t-test
B) Independent t-test
C) Need more information

Question 16

Fifteen sets of identical twins are the subjects in a drug experiment. One twin receives the treatment, and the other twin receives a placebo. What type of t-test should be conducted?

A) Dependent t-test
B) Independent t-test
C) Need more information

Question 17

Fifteen sets of identical twins are the subjects in a drug experiment. One twin receives the treatment, and the other twin receives a placebo. What are the degrees of freedom for the appropriate t-test?

A) 14
B) 15
C) 28
D) 29
E) 30