Time Spent using e-mail each session is normally distributed, with µ = 8 minutes and σ = 2 minutes. If you choose a random sample of 25 sessions,
a) Find out the probability that the sample mean is between 7.8 and 8.2 minutes?
b) Determine the probability that the sample mean is between 7.5 and 8 minutes?
c) If you choose a random sample of 100 sessions, determine the probability that the sample mean is between 7.8 and 8.2 minutes?
d) Describe the difference in result of (a) and (b).