Question

1. Which effect size measure should be used if the researcher wants to understand how much variability is explained by the treatment?

Cohen's d

any of these

r-squared

a confidence interval

2.

Which of the follow is NOT an assumption of the independent samples t-test?

Group of answer choices

The observations within each sample must be independent

The populations from which the samples are drawn must be normal

The populations from which the samples are drawn must have equal variances

The samples must have the same sample size

Answer 1

1. Cohen's d

Cohen's d is the appropriate effect size to measure the variability between two means.

2. The population from which the samples are drawn must be normal.

Why other options are incorrect?

The observations within each sample must be independent is totally unnecessary condition.

To conduct the test, normality assumption is necessary.

Equality of variances is not a necessary condition, we can use Welch t test in case variances are not equal.

Equality of sample sizes is also an unnecessary condition.