Question: Suppose we’re interested in the effect of practice on public speaking anxiety. We recruit eight volunteers and pretest them on public speaking anxiety on a standardized test. We then provide the volunteers with several practice sessions in giving speeches and test them again. To see if the practice causes a lasting change in their anxiety, we administer a follow-up test 6 months later. Here are the data (higher scores indicate higher anxiety):
Compute F and test it for significance. If F is significant, use the LSD to do all pairwise comparisons.