Later on, the forester in Exercise 39 shows you a histogram of the tree diameters he used in analyzing the woods that was for sale. Do you think he was justified in using a Normal model?

Data From Exercise 39

A forester measured 27 of the trees in a large woods that  is up for sale. He found a mean diameter of 10.4 inches and a  standard deviation of 4.7 inches. Suppose that these trees provide  an accurate description of the whole forest and that a  Normal model applies.
a) Draw the Normal model for tree diameters.
b) What size would you expect the central 95% of all trees  to be?
c) About what percent of the trees should be less than an inch  in diameter?
d) About what percent of the trees should be between 5.8 and  10.4 inches in diameter?
e) About what percent of the trees should be over 15 inches in  diameter?

Transcribed Image Text:

A 3 لا # of Trees N 0.0 4.5 Ho 13.5 9.0 Diameter (in.) 18.0