An accurate assessment of oxygen consumption provides important information for determin...

An accurate assessment of oxygen consumption provides important information for determining energy expenditure requirements for physically demanding tasks. The paper “Oxygen Consumption During Fire Suppression: Error of Heart Rate Estimation” (Ergonomics [1991]: 1469–1474) reported on a study in which x = oxygen consumption (in milliliters per kilogram per minute) during a treadmill test was determined for a sample of 10 fire fighters. Then y = oxygen consumption at a comparable heart rate was measured for each of the 10 individuals while they performed a fire-suppression simulation. This resulted in the following data and scatterplot:

a. Does the scatterplot suggest an approximate linear relationship?

b. The investigators fit a least-squares line. The resulting Minitab output is given in the following:

Predict fire-simulation consumption when treadmill consumption is 40.

c. How effectively does a straight line summarize the relationship?

d. Delete the first observation, (51.3, 49.3), and calculate the new equation of the least-squares line and the value of r². What do you conclude? (Hint: For the original data, Σx = 388.8, Σy = 310.3, Σx² = 15,338.54, Σ xy = 12,306.58, and Σy² = 10,072.41.)