According to the World Health Organization, obesity has reached epidemic proportions globally. While obesity has generally been linked with chronic disease and disability, researchers argue that it may also affect salaries. In other words, the body mass index (BMI) of an employee is a predictor for salary. (A person is considered overweight if his/her BMI is at least 25 and Obese if BMI exceeds 30.) The accompanying table shows a portion of salary data for 30 college-educated men with their respective BMI and a dummy variable that equals 1 for a white man and 0 otherwise.

Salary ($1,000).................... BMI.......... Race

34...................................... 33............... 1

43...................................... 26............... 1

⋮....................................................... ⋮..................... ⋮

45...................................... 21............... 1

a. Estimate a model for Salary using BMI and Race as the explanatory variables. Determine if BMI influences salary at the 5% level of significance.

b. What is the estimated salary of a white collegeeducated man with a BMI of 30? Compute the corresponding salary of a nonwhite man.