For a random sample of 36 graduates of the Police Academy, their scores on the pistol range have a mean of 75 with a standard deviation of 7.2. Using the information given to determine a preliminary estimate of o, we want to determine the sample size needed so that X and / do not differ by more than 1 with 95% confidence. The critical value used in the sample size formula is O qt(0.975,35) O qt(0.05,35) O qt(0.025,35) O qnorm(0.975)