statistics management

In many ways, comparing multiple sample means is simply an extension of what we covered last week.  What situations exist where a multiple (more than two) group comparison would be appropriate? (Note: Situations could relate to your work, home life, social groups, etc.).  Create a null and alternate hypothesis for one of these issues.  What would the results tell you?

Effect Size

Several statistical tests have a way to measure effect size.  What is this, and when might you want to use it in looking at results from these tests on job related data?