Lecture 30: Hypothesis Testing About Difference of Two Population Means

Question 1

What are the 4 assumptions for hypothesis testing about the difference of two population means?

Answer 1

*random samples from each of the population is drawn

*sample individuals are independent of each other

*both populations are normal or we need reasonably large samples
to validate using the CLT

*both population distributions have equal variances

Question 2

What assumption does the pooled standard deviation require?

Answer 2

That the population variances are equal.