A severe drought has affected several western states in rece…

A severe drought has affected several western states in recent years.  A Christmas tree farmer is worried about the drought’s effect on the size of his trees.  To determine whether the growth of his trees has been reduced by the drought, the farmer decides to take a sample of the heights of 6 trees and obtains the following results (recorded in inches): Tree Height 1 60 2 57 3 62 4 69 5 46 6 54 Find the standard deviation of the heights of this sample of 6 trees.