Short Answer: Show all of your work in the space provided or upload your responses and
work at the end of the exam.
In the dessert city of Cactuslandia, they have kept rainfall records for the past 95 years. The
distribution of annual rainfall is approximately normal and has no outliers. The minimum of 2.3 inches
occurred in 1961 and the maximum of 8.9 inches occurred in 1942.
A. What is the approximate average annual rainfall over the last 95 years?
B. What is a reasonable estimate for the standard deviation of this rainfall distribution?
C. Anything over 7.8 inches is considered a very wet year. Approximately how many of the past
95 years had annual rainfall that exceeded 7.8 inches?
HINT: DRAW THE PICTURE OF THE NORMAL CURVE