Army Physical Fitness Test consists of 2 minutes of pushups followed by 2 minutes of situps followed by a 2-mile run. There were n = 84 participants. You fit a multiple linear regression model (Y = B0+B1x1+B2x2+E)to predict the time (in seconds) it takes to complete the 2-mile run for a participant based on the number of situps and the number of pushups performed by a participant. Here are the estimates of the parameters b0 = 1095.5384, b1 = -2.618696, b2 = -0.883433, and R2 = 0.69 where the response variable y is the run time, x1 is the number of pushups, and x2 is the number of situps.
(a) Give an interpretation of b1 in the context of the problem.
(b) Give an interpretation of R2 in the context of the problem.