Unit 3 Question 5

Let's assume there are 20 people in the "smashed" sample, and they had a variance of s² = 9.8. And, there are 30 people in the "hit" sample, and they had a variance of s² = 15.2.

Explain pooled variance.

Then, answer these questions:

Will the pooled variance be closer to 9.8 or 15.2?

How do you know?

Scenario:

In 1974, Loftus and Palmer conducted a classic study demonstrating how language used to ask a question can influence eyewitness memory. In the study, college students watched a film of an autombile accident and then were asked questions about what they saw. One group was asked, "About how fast were the cars when they smashed into each other?" Another group were asked, "About how fast were the cars when they hit each other?" The "smashed into" group reported significantly higher estimates of speed than the "hit" group.