Problem: The average serve speed in men's tennis is 135 mph with a standard deviation of 6.5 mph. We develop a new training method to increase arm strength and (hopefully) speed of the serve. We recruit 9 professional tennis players to try our method. After 6 months, we test the speed of their serves and get a sample mean of 138 mph.

1. Test the hypothesis that the training method effects serve speed. Use = .05. All steps for hypothesis testing!

2. Think about ways to increase power in this scenario. Which of these options would allow us to Reject Ho? Check each of the parameters using the Z Test calculator and see what happens to the results. -Options: change alpha, change from 2-to 1-tailed, increase n, increase mean difference, reduce variability

-Report what you tried and how that changed your ability to detect a difference (Reject Ho).