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.

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. (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