The average diameter of sand dollars on a certain island is 3.00 centimeters with a standard deviationof 0.70 centimeters. If 9 sand dollars are chosen at random for a collection, find the probabilitythat the average diameter of those sand dollars is more than 2.790 centimeters. Assume that the variable is normally distributed.

Denote by Xbar the average diameter of those sand dollars. Then Xbar follows a normal …

This solution calculates the probability that the average diameter of a sand dollar is more then 2.790 centimeters.