Question 2.

Time spent using e-mail per session is normally distributed with = 8 minutes and = 2 minutes.

If you select a random sample of 16 sessions, a) What is the probability that the sample mean is between 7.8 and 8.2 minutes? b) What is the probability that the sample mean is between 7.5 and 8 minutes? c) If you select a random sample of 100 sessions, what is the probability that the sample means

is between 7.8 and 8.2 minutes? d) Explain the difference in the results of (a) and (c).