The time for a visitor to read health instructions on a web site is approximately normally distributed with a mean of 10 minutes and a standard deviation of 2 minutes. suppose 64 visitors independently view the site. determine the following:
a. the expected value and the variance of the mean time of the visitors.
b. the probability that the mean time of the visitors is within 15 seconds of 10 minutes
c. the value exceeded by the mean time of the visitors with probability 0.01