Question 1

Which statistical test would be most appropriate to compare the mean scores of two independent groups in a clinical trial evaluating a new drug for multiple sclerosis?

Accepted Answer

Independent samples t-test

Question 2

A researcher wants to determine if a new rehabilitation program improves walking distance in patients with COPD. The same patients are measured before and after the program. Which test should be used?

Accepted Answer

Repeated measures t-test (paired t-test)

Question 3

Which of the following is a key assumption for parametric tests such as the independent samples t-test?

Accepted Answer

The variances of the two groups are equal

Question 4

In hypothesis testing, what does the null hypothesis ($$H_0) $$typically state when comparing two group means?

Accepted Answer

$$H_0$$: \$$mu_1$$ = \$$mu_2$

Question 5

A researcher performs an independent samples t-test and finds $$p \u003c 0.05. $$What is the most appropriate interpretation?

Accepted Answer

The null hypothesis is rejected; there is a significant difference between the group means

Question 6

Which formula represents the calculation of the t-statistic for independent samples with equal variances?

Accepted Answer

$$t = \frac{\bar{x}_1 - \bar{x}_2}{\sqrt{s_p^2$ \left( \frac{1}{n_1$} + \frac{1}{n_2$} \right)}}$$

Question 7

If the variances between two groups are not equal, which adjustment should be made when performing an independent samples t-test?

Accepted Answer

Apply Welch's t-test

Question 8

Which of the following is a non-parametric alternative to the independent samples t-test?

Accepted Answer

Mann-Whitney U test

Question 9

A researcher uses SPSS to analyze the difference in means between two groups. What is the first step to verify before interpreting the t-test results?

Accepted Answer

Verify the result of the Levene's test for equality of variances

Question 10

Which effect size measure is commonly calculated after a t-test to assess the magnitude of the difference between two means?

Accepted Answer

Cohen's d

Question 11

A study compares the mean blood pressure of patients before and after a new medication. The same patients are measured twice. Which formula should be used for the paired t-test?

Accepted Answer

$$t = \frac{\bar{d}}{s_d / \sqrt{n}}$$

Question 12

Which of the following scenarios would require the use of a repeated measures t-test?

Accepted Answer

Comparing cholesterol levels in the same group before and after a diet intervention

Question 13

What is the main difference between parametric and non-parametric tests?

Accepted Answer

Parametric tests require data to be normally distributed; non-parametric tests do not

Question 14

A researcher finds a large Cohen's d after a t-test. What does this indicate?

Accepted Answer

The magnitude of the difference between group means is large

Question 15

Which of the following is NOT a step in verifying the results of a t-test using SPSS?

Accepted Answer

Ignore the assumption of normality

Question 16

If the p-value from a t-test is greater than 0.05, what should the researcher conclude?

Accepted Answer

The null hypothesis cannot be rejected

Question 17

Which of the following best describes the alternative hypothesis ($$H_1) in a $$two-sample t-test?

Accepted Answer

$$H_1$$: \$$mu_1$$ 
eq \$$mu_2$

Question 18

A researcher is interested in the effect of intensive rehabilitation on patients with chronic obstructive pulmonary disease (COPD). Which statistical test should be used to compare the mean walking distance before and after rehabilitation in the same patients?

Accepted Answer

Repeated measures t-test (paired t-test)

Question 19

Which of the following is a correct interpretation if the effect size calculated after a t-test is small?

Accepted Answer

The difference between group means is small, regardless of statistical significance

Statistical Methods for Mean Differences in Health Sciences

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