According to a social media? blog, time spent on a certain social networking website has a mean of 18 minutes per visit. Assume that time spent on the social networking site per visit is normally distributed and that the standard deviation is 3 minutes. Complete parts? (a) through? (d) below.
a. If you select a random sample of 25 ?sessions, what is the probability that the sample mean is between 17.5 and 18.5?
b. If you select a random sample of 25 sessions, what is the probability that the sample mean is between 17 and 18 ?minutes?
c. If you select a random sample of 100 ?sessions, what is the probability that the sample mean is between 17.5 and 18.5 ?minutes?