The personnel director for McCormick Publisher Services developed the following estimated regression equation relating an employee's score on a job satisfaction test to his or her length of service and pay grade.

= 14.4 - 8.69x1 + 13.5x2

Where

x1 = length of service (years)

x2 = pay grade

y = job satisfaction test score (higher scores indicate greater job satisfaction)

a. Interpret the coefficients in this estimated regression equation.

b. Predict the job satisfaction test score for an employee who has four years of service and has a pay grade of 6?