118. The article Validation of the Rockport Fitness Walking Test in College Males and Females (Res.

Q. Exercise Sport, 1994: 152—158) recommended the following estimated regression equation for relating y  VO2max (L/min, a measure of cardiorespiratory tness) to the predictors x1  gender

(female  0, male  1), x2  weight (lb), x3 

1-mile walk time (min), and x4  heart rate at the end of the walk (beats/min):

a. How would you interpret the estimated coef cient 0996?

b. How would you interpret the estimated coef cient  .6566?

c. Suppose that an observation made on a male whose weightwas 170 lb,walk timewas 11 min, and heart rate was 140 beats/min resulted in VO2max  3.15. What would you have predicted for VO2max in this situation, and what is the value of the corresponding residual?

d. Using SSE  30.1033 and SST  102.3922, what proportion of observed variation in VO2max can be attributed to the model relationship?

e. Assuming a sample size of n  20, carry out a test of hypotheses to decide whether the chosen model speci es a useful relationship between VO2max and at least one of the predictors.