Thompson Photo Works purchased several new, highly sophisticated processing machines. The production department needed some guidance with respect to qualifications needed by an operator. Is age a factor? Is the length of service as an operator (in years) important? In order to explore further the factors needed to estimate performance on the new processing machines, four variables were considered:

X1 = Length of time an employee was in the industry

X2 = Mechanical aptitude test score

X3 = Prior on-the-job rating

X4 = Age

Performance on the new machine is designated Y.

Thirty employees were selected at random. Data were collected for each, and their

performances on the new machines were recorded. The following multiple regression equation was estimated:

Y = 11.6 + 0.4 X1 + 0.286 X2 + 0.112 X3 + 0.002 X4.

a. How many dependent variables are there? Independent variables?

b. What is the number 0.286 called?

c. As age increases by one year, how much does estimated performance on the new machine increase?

d. Carl Knox applied for a job at Photo Works. He has been in the business for 6 years (X1) and scored 280 on the mechanical aptitude test (X2). Carl’s prior on-the-job performance rating is 97 (X3), and he is 35 years old (X4). Estimate Carl’s performance on the new machine.

Coefficients needed to perform the calculations.

Variable Coefficient Carl Knox
Intercept 11.6
X1 0.4 6
X2 0.286 280
X3 0.112 97
X4 0.002 35