Question 1

Which of the following best describes the main purpose of a paired-samples t test?

Accepted Answer

To compare the means of two related groups where each participant is in both samples.

Question 2

In a study measuring the effect of a new teaching method, students' test scores are recorded before and after the intervention. Which statistical test is most appropriate for analyzing the difference in scores?

Accepted Answer

Paired-samples t test

Question 3

What is the formula for calculating the test statistic in a paired-samples t test?

Accepted Answer

$t = \frac{M_{difference} - \mu_{difference}}{s_M}$

Question 4

Which assumption is NOT required for a paired-samples t test?

Accepted Answer

The two samples are independent of each other.

Question 5

A researcher wants to test whether a memory training program improves recall. She measures recall before and after the program for each participant. What is the null hypothesis for the paired-samples t test?

Accepted Answer

The mean recall before and after the program are equal.

Question 6

Given $M_{difference} = 0.2$, $s = 0.141$, and $s_M = 0.063$, what is the value of the paired-samples t statistic?

Accepted Answer

$t = 3.17$

Question 7

If the calculated t statistic is 3.17 and the critical values for a two-tailed test at $p = 0.05$ are $\pm 2.776$, what is the correct decision?

Accepted Answer

Reject the null hypothesis.

Question 8

What is the effect size formula (Cohen's d) for a paired-samples t test?

Accepted Answer

$d = \frac{M_{difference} - \mu_{difference}}{s}$

Question 9

Which of the following best describes 'order effects' in a within-groups design?

Accepted Answer

The change in participant behavior when the dependent variable is presented for a second time.

Question 10

How does counterbalancing help in within-groups research designs?

Accepted Answer

It minimizes order effects by varying the order of presentation of the independent variable.

Question 11

Which step in the paired-samples t test involves stating the null and research hypotheses?

Accepted Answer

Step 2

Question 12

What is the degrees of freedom ($df$) for a paired-samples t test with 5 pairs of scores?

Accepted Answer

$df = 4$

Question 13

Which of the following is a real-world example where a paired-samples t test would be appropriate?

Accepted Answer

Comparing cholesterol levels in patients before and after taking a new medication.

Question 14

What is the main difference between a paired-samples t test and an independent-samples t test?

Accepted Answer

Paired-samples t test compares means from the same participants; independent-samples t test compares means from different participants.

Question 15

When calculating a confidence interval for a paired-samples t test, what is the first step?

Accepted Answer

Draw a normal curve with the sample difference between the means in the center.

Question 16

If a paired-samples t test yields a large effect size (Cohen's d), what does this indicate?

Accepted Answer

The difference between the paired means is large relative to the variability.

Question 17

Which of the following is NOT a step in calculating a paired-samples t test?

Accepted Answer

Calculate the correlation coefficient.

Question 18

Why must researchers be cautious when generalizing findings from a paired-samples t test if participants were not randomly selected?

Accepted Answer

Because the results may not represent the broader population.

Question 19

Which of the following is a correct interpretation of a 95% confidence interval for the mean difference in a paired-samples t test?

Accepted Answer

If the study were repeated many times, 95% of the calculated intervals would contain the true mean difference.

Paired-Samples t Test: Concepts and Procedures

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