Chapter 4: Q. 4.114 (page 182)
In Exercises 4.104 - 4.115, use the technology of your choice to perform the following tasks.
(a) Decide whether finding the regression line for the data is reasonable. If so, 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.
In the paper 鈥淭otal Body Composition by Dual-Photon (153Gd) Absorptiometry鈥 (American Journal of Clinical Nutrition, Vol. 40, pp. 834鈥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鈥檚 age and percentage of body fat are shown on the WeissStats CD.
Short Answer
(a) From the scatterplot, it is reasonable to find the regression line for the data since the observations are around the line.
(b) The coefficient of determination is 0.627.
(c) The percentage of variation in the observed values of the response variable explained by the regression is 62.7%.
(d)The regression equation is useful for making predictions because the percentage of variation in the observed values of the response variable explained by the regression is 62.7%which is greater than 50%.


