For each question, construct a normal distribution curve and label the horizontal axis. Then answer each
question.
1. The shelf life of a particular dairy product is normally distributed with a mean of 12 days and a standard
deviation of 3 days.
a. About what percent of the products last between 9 and 15 days?
b. About what percent of the products last between 12 and 15 days?
c. About what percent of the products last 6 days or less?
d. About what percent of the products last 15 or more days?
2. A line up for tickets to a local concert had an average (mean) waiting time of 20 minutes with a standard
deviation of 4 minutes.
a. What percentage of the people in line waited for more than 28 minutes?
b. If 2000 ticket buyers were in line, how many of them would expect to wait for less than 16
minutes?
3. On a recent math test, the mean score was 75 and the standard deviation was 5. Mike scored an 85.
a. What percent of the students scored below Mike?
b. What percent of the students scored above Mike?
c. If the class had 150 students in it, how many of them would you expect to score higher than
Mike?
d. If the class had 220 students in it, how many of them would you expect to score lower than
Mike?