The US Census Bureau in a study of the effect of education on income, in 2005 the mean

income (in thousands of dollars) for workers of age 18 and older approximately followed

the formula yhat = 20 + 23e + 17s where e=1 for college graduates and e=0 for high

school graduates and s=1 for men and s=0 for women. Approximate the mean income

for women that are high school graduates and then approximate the mean income for

women that are college graduate