1. We have a random sample of 30 12^th grade students who can do 25 pushups on average, with a sample standard deviation of 9, after completing a special physical education program. Does this value of 25 differ significantly from the population value of 20?

• What kind of test can we use?
• What is the test value?
• Write down the null and alternative hypotheses.
• Find the critical value (make sure it is a one-tailed or two-tailed test).
• Calculate the test statistics.
• Answer the research question: "Does this value of 25 differ significantly from the population value of 20?"
• Calculate the Cohen's d effect size.