A person’s muscle mass is expected to decrease with age. To explore this relationship
in women, a nutritionist randomly selected 15 women from each l0-year age group,
beginning with age 40 and ending with age 79. Each woman’s muscle mass was then measured using a standard technique. The goal of this analysis was to determine if a polynomial regression model would do an adequate job of describing the relationship between Y (muscle mass) and X (age). The variables in the data set are as follows:
AGE: age in years
MUSC_MASS: muscle mass
Based on the following scatterplot, which would you say that the quadratic model (solid line) fits the data well? Give a reason for your answer.