Question 7

The waiting time at a certain bank is normally distributed with a mean of 3.7 minutes with a standard deviation of 1.4 minutes. If a group of 40 people are polled, what is the probability that the mean waiting time for this sample is less than 3 minutes?

Question 8

The number of cigarettes smoked per day by adults forms a normal distribution. The average number of cigarettes smoked per day is 20 with a standard deviation of 7 cigarettes. If a sample of 32 adults are polled, what is the probability that the sample mean number of cigarettes smoked is more than 19?