Refer to the American Mineralogist (October 2009) study of the evolution of uranium minerals in the Earth’s crust, Exercise 5.17. Recall that researchers estimate that the trace amount of uranium Y in reservoirs follows a uniform distribution ranging between 1 and 3 parts per million. In a random sample of n = 60 reservoirs, let Y̅ represent the sample mean amount of uranium.
a. Find E(Y̅) and interpret its value.
b. Find Var (Y̅) .
c. Describe the shape of the sampling distribution of Y̅.
d. Find the probability that Y̅ is between 1.5 ppm and 2.5 ppm.
e. Find the probability that Y̅ exceeds 2.2 ppm.

Data from Exercise 5.17

The American Mineralogist (October 2009) published a study of the evolution of uranium minerals in the Earth’s crust. Researchers estimate that the trace amount of uranium Y in reservoirs follows a uniform distribution ranging between 1 and 3 parts per million.