Refer to Exercise 11.48. a. Predict the actual tree volume for a tree the assistant...

Refer to Exercise 11.48.

a. Predict the actual tree volume for a tree the assistant estimates to have a cubic-foot volume of 13.

b. Place a 95% prediction interval on x, the actual tree volume in part (a).

REFERENCE:

11.48 : A forester has become adept at estimating the volume (in cubic feet) of trees on a particular site prior to a timber sale. Since his operation has now expanded, he would like to train another person to assist in estimating the cubic-foot volume of trees. He decides to calibrate his assistant’s estimations of actual tree volume. The forester selects a random sample of trees soon to be felled. For each tree, the assistant is to guess the cubic-foot volume y. The forester also obtains the actual cubic-foot volume x after the tree has been chopped down. From these data, the forester obtains the calibration curve for the model

In the near future he can then use the calibration curve to correct the assistant’s estimates of tree volumes. The sample data are summarized here.

Fit the calibration curve using the method of least squares. Do the data indicate that the slope is significantly greater than 0? Use α = .05.