This specification does not allow for the possibility that there may be an interaction that occurs between the two qualitative variables, D2 and D3. For example, a female who is married may earn wages that differ from those of an unmarried male by an amount that is not the same as the sum of the differentials for solely being female and solely being married. Then the effect of the interacting dummies on the mean of Y is not simply "additive" as in the case of the above specification, but "multiplicative" also, and the determination of wages can be specified as: