To estimate the amount of lumber in a tract of timber, an owner decided to count the

Question:

To estimate the amount of lumber in a tract of timber, an owner decided to count the number of trees with diameters exceeding 12 inches in randomly selected 50-by-50-foot squares. Seventy 50-by-50-foot squares were chosen, and the selected trees were counted in each tract. The data are listed here:

a. Construct a relative frequency histogram to describe the data.
b. Calculate the sample mean as an estimate of µ, the mean number of timber trees for all 50-by-50-foot squares in the tract.
c. Calculate s for the data. Construct the intervals ± s, ± 2s, and ± 3s.
Calculate the percentage of squares falling into each of the three intervals, and compare with the corresponding percentages given by the Empirical Rule and Tchebysheff's Theorem.