A job evaluation plan in the Dorben Company provides for five labor grades, of which grade 5 has the highest base rates and grade 1 the lowest. The linear plan involves a range of 50 to 250 points for skill, 15 to 75 points for effort, 20 to 100 points for responsibility, and 15 to 75 points for job conditions. Each of the four factors has five degrees. Each labor grade has three money rates: a 'low,' a 'mean,' and a 'high' rate.
a) If the high money rate of labor grade 1 is $8 per hour and the high money rate of labor grade 5 is $20 per hour, what would be the mean money rate of labor grade 3?
b) What degree of skill is required for a labor grade of 4 if second-degree effort, second-degree responsibility, and first-degree job conditions apply?