DS 12.2.3 is a data set concerning the aerobic fitness of a sample of 20 male subjects. An exercising individual breathes through an apparatus that measures the amount of oxygen in the inhaled air that is used by the individual. The maximum value per unit time of the utilized oxygen is then scaled by the person's body weight to come up with a variable V02 max. which is a general indication of the aerobic fitness of the individual.
(a) Fit a linear regression model with V02-max as the dependent variable and age as the explanatory variable.
(b) Does the sign of β^1 surprise you? What does your model predict as the change in VO2-max for an additional five years of age?
(c) What VO2-max value would you predict for a 50-year-old man?
(d) What does the model tell you about the aerobic fitness of a 15-year-old boy?
(e) What is the estimate of the error variance?
(This problem is continued in Problems 12.3.5, 12.4.5,12.5.4,12.6.7, 12.7.3, and 12.9.5.)