In the paper "Total Body Composition by Dual-Photon (153Gd) Absorptiometry" (American Journal of Clinical Nutrition, Vol. 40, pp. 834-839), R. Mazess et al. studied methods for quantifying body composition. Eighteen randomly selected adults were measured for percentage of body fat, using dual-photon absorptiometry. Each adult's age and percentage of body fat are shown on the WeissStats CD.
a. Decide whether finding a regression line for the data is reasonable. If so, then also do parts (b)–(d).
b. Obtain the coefficient of determination.
c. Determine the percentage of variation in the observed values of the response variable explained by the regression, and interpret your answer.
d. State how useful the regression equation appears to be for making predictions.