In the application presented in this section, one of Jacob Mincer's specifications relating earnings to schooling and workplace experience is
In E = 4.9 + 0.26S - 0.003S2- 0.004XS + 0.15X - 0.002X2.
(a) What is the partial derivative of the logarithm of earnings with respect to experience?
(b) What is the percentage impact on earnings due to a one year increase in experience if S = 20 and X = 5?
(c) What is the impact on the dollar value of earnings due to a one year increase in experience if S = 20 and X = 5?
(d) What is the percentage impact on earnings due to an increase in experience of 1% if S = 20 and X = 5?
(e) Does this specification exhibit diminishing marginal returns to earnings with regard to experience?