# Question: In the paper Total Body Composition by Dual Photon 153Gd Absorptiometry

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.

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.

## Answer to relevant Questions

J. Greene and J. Touchstone conducted a study on the relationship between the estriol levels of pregnant women and the birth weights of their children. Their findings, "Urinary Tract Estriol: An Index of Placental Function," ...The coefficient of determination of a set of data points is 0.709 and the slope of the regression line is −3.58. Determine the linear correlation coefficient of the data. a. Definition 4.7 on page 171. b. Formula 4.3 on page 171. Compare your answers in parts (a) and (b). Consider the following set of data points. a. Compute the linear correlation coefficient, r. b. Can you conclude from your answer in part (a) that the variables x and y are unrelated? Explain your answer. c. Draw a ...y = −1 + 2x a. Find the y-intercept and slope. b. Determine whether the line slopes upward, slopes downward, or is horizontal, without graphing the equation. c. Use two points to graph the equation.Post your question