F I L E According to th e U.S. D epartm ent of Health and Hum an Services, African-American w om en have th e highest rates of being overw eight com pared to o th er groups in th e U.S.

Individuals are considered overw eight if their body m ass index (BMI) is 25 or greater. Consider th e following data on BMI of 120 individuals and th e corresponding g en d er and race dum m ies. The com plete data, labeled Overweight, can be found on th e text w ebsite.

BMI Female Black 28.70 0 1 28.31 0 0

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24.90 0 1 N ote: Fem ale = 1 for fe m a les a n d 0 for m ales: Black = 1 for African A m ericans a n d 0 o th erw ise .

a. Estim ate th e m odel, BMI = β 0 + β 1 Female + β 2Black

+ β3(Female × Black) + ε , to predict th e BMI for w hite males, w hite fem ales, black males, and black females.

b. Is th e difference b etw een w hite fem ales and w hite m ales statistically significant at th e 5% level?

c. Is th e difference b etw een w hite m ales and black m ales statistically significant at th e 5% level?