Consider the following economic model describing workers' earnings: In(earning) = 0 + B female + B,age + .educ + 8 age .female + 0 female .educ + 0 age With all the variables described as follows: In(eaming) = log of worker's earning: female = 1 if worker is female, and 0 if male; educ = years of schooling; age = age of the worker; age = age age female.educ is an interaction variable equal to female *educ; age.female is an interaction variable equal to age fomale