Ring shake, which is the separation of the wood between growth rings, is a serious problem in hemlock trees. Researchers have developed the following function that estimates the probability P that a given hemlock tree has ring shake.

where A is the age of the tree (yr), B is 1 if bird pecking is present and 0 otherwise, and D is the diameter (in.) of the tree at breast height.

(a) Estimate the probability that a 150-year-old tree, with bird pecking present and a breast height diameter of 20 in., will have ring shake.
(b) Estimate the probability that a 150-year-old tree, with no presence of bird pecking and a breast height diameter of 20 in., will have ring shake.
(c) Develop a statement about what can be said about the influence that the three variables have on the probability of ring shake.

Transcribed Image Text:

P(A, B, D) = 1 1 + €3.68-0.016A-0.77B—0.12D '