# The Process of Statistical Analysis in Psychology

# Study Questions

## Short Answer

1. What are the similarities and differences between independent samples *t* test and related/paired samples *t* test?

Ans: In both independent samples and paired samples *t* tests, a researcher is comparing means from two groups. The difference is that independent samples *t* test is used when one group is not related, in any way, to the group that is being compared, whereas for the related samples *t* test, the score in one group is somehow related to another score in the other group.

Learning Objective: 11-1: How can we compare two different populations in a research study?

Cognitive Domain: Comprehension

Answer Location: Independent Samples

2. Why does an independent samples *t* test use the pooled variance? What is the assumption that is crucial for using the pooled variance?

Ans: You use a pooled variance in independent samples because you have two sets of variances. Homogeneity of variance assumption allows us to use the pooled variance in independent samples *t* test.

Learning Objective: 11-4: What is the pooled variance and how does it help us handle unequal sample sizes in our hypothesis test?

Cognitive Domain: Comprehension

Answer Location: Step 4: Calculate Statistics | Test Assumptions