a. Conduct a regression analysis with income (RINCOME) as the dependent variable and age (AGE), education (EDUC), number of hours of work (HRS1), and whether someone worked for him or herself (WRKSLF: 1 = Self, 2 = Someone else) as independent variables.

b. Interpret the coefficient of WRKSLF.

c. Is there sufficient evidence to infer that people who work for themselves earn larger incomes after removing the effect of age, education, and weekly hours of work?