A physician was interested in examining the relationship between the work performed by ­individuals in an exercise tolerance test and the excess weight (as determined by standard weight– height tables) they carried. To do this, a random sample of 28 healthy adult females, ranging in age from 25 to 40, was selected from the community clinic during routine visits for physical ­examinations. The selection process was restricted so that seven persons were selected from each of the following weight classifications:
Normal weight (less than 10% underweight)
1%– 10% overweight
11%– 20% overweight
More than 20% overweight
As part of the physical examination, each person was required to exercise on a bicycle ergometer until the onset of fatigue. The time to fatigue (in minutes) was recorded for each person. The data are given next.
Classification Fatigue Time
Normal………………….. 25, 28, 19, 27, 23, 30, 35
1%– 10% overweight…… 24, 26, 18, 16, 14, 12, 17
11%– 20% overweight…. 15, 18, 17, 25, 12, 10, 23
More than 20% overweight… 10, 9, 18, 14, 6, 4, 15
a. Identify the experimental design and write an appropriate statistical model.
b. Use α = .05 and perform an analysis of variance.