1. A forester wishes to predict the volume (in cubic feet) of usable lumber in a certain species of tree using the height (in feet) and diameter (in inches) of the trees. The height and diameter of 31 trees of a certain species were measured, the trees were cut down, and the volume of usable lumber was determined. The explanatory variable(s) in this study are

A. either height or diameter.
B. both height and diameter.
C. height, diameter, and volume.

2. An old saying in golf is "you drive for show and you putt for dough." The point is that good putting is more important than long driving for shooting low scores and hence winning money. To explore the relation between winning, putting, and driving distance, data on the top 69 money winners on the PGA tour in 1993 are used. The average number of putts per hole for each player and their average driving distance is used to predict their total winnings using the multiple regression model

where the deviations εI are assumed to be independent and Normally distributed with mean 0 and standard deviation σ. This model was fit to the data using the method of least squares. The following results were obtained from statistical software.

To see if higher winnings are associated with fewer putts, the researchers decided to test the hypotheses H0: β1 = 0 , Ha: β1 < 0. The P-value of the test is
A. less than 0.0005.
B. between 0.0005 and 0.01.
C. greater than 0.01.