The data set cherry.dat, from Hand et al. (1994), contains measurements of diameter (inches), height (feet), and timber volume (cubic feet) for a sample of 31 black cherry trees. Diameter and height of trees are easily measured, but volume is more difficult to measure.
a Plot volume vs. diameter for the 31 trees.
b Suppose that these trees are an SRS from a forest of N = 2967 trees and that the sum of the diameters for all trees in the forest is tx = 41,835 inches. Use ratio estimation to estimate the total volume for all trees in the forest. Give a 95% CI.
c Use regression estimation to estimate the total volume for all trees in the forest. Give a 95% CI.