If you set the *= value in the B_f B instead of Equation 3 to study the factors that caused the sexual discrimination. The equation for the differences of men and women workers wage is equivalent to equation 4.
If the B ^ * = B_f represented in equation 3 to determine the factors that caused by gender discrimination, so that the difference between the wages of men and women to Equation 4.
If the B * = B_f instead in the equation 3 to study factors caused by sexual discrimination. So, difference equation of wages for women and men. Is equal to the 4.