Cardiorespiratory fitness is widely recognized as a major component of overall physical well-being. Direct measurement of maximal oxygen uptake (VO2max) is the single best measure of such fitness, but direct measurement is time-consuming and expensive. It is therefore desirable to have a prediction equation for VO2max in terms of easily obtained quantities. Consider the variables y = VO2max (L/min) x1 = weight (kg) x2 = age (yr) x3 = time necessary to walk 1 mile (min) x4 = heart rate at the end of the walk (beats/min)

Consider the regression equation for the VO_2 max d male students: yHAT = 5.0 + 0.005x1 0.05x2 0.09x3 0.01x4

(a) Interpret the estimate for 1. Holding all other variables constant, a 0.005 kg increase in weight will result in a 1 L/min decrease in VO2max. Holding all other variables constant, a 1 kg increase in weight will result in a 0.005 L/min increase in VO2max. Holding all other variables constant, a 1 kg increase in weight will result in a 0.005 L/min decrease in VO2max. Holding all other variables constant, a 0.005 kg increase in weight will result in a 1 L/min increase in VO2max. Correct: Your answer is correct.

Interpret the estimate for 3. Holding all other variables constant, a 1 min increase in walk time will result in a 0.09 L/min decrease in VO2max. Holding all other variables constant, a 0.09 min increase in walk time will result in a 1 L/min decrease in VO2max. Holding all other variables constant, a 0.09 min increase in walk time will result in a 1 L/min increase in VO2max. Holding all other variables constant, a 1 min increase in walk time will result in a 0.09 L/min increase in VO2max. Correct: Your answer is correct.

(b) What is the predicted value of VO2max, y, when weight is 77 kg, age is 19 yr, walk time is 11 min, and heart rate is 130 b/m? L/min