Refer to the Johnson Filtration problem introduced in this section. Suppose that in addition to information on the number of months since the machine was serviced and whether a mechanical or an electrical repair was necessary, the managers obtained a list showing which repairperson performed the service. The revised data follow.
Repair time in hours Months since last service Type of Repair Repair Person
2.9 2 Electrical Dave Newton
3.0 6 Mechanical Dave Newton
4.8 8 Electrical Bob Jones
1.8 3 Mechanical David Newton
2.9 2 Electrical David Newton
4.9 7 Electrical Bob Jones
4.2 9 Mechanical Bob Jones
4.8 8 Mechanical Bob Jones
4.4 4 Electrical Bob Jones
4.5 6 Electrical David Newton
a. Clearly specify the dependent variable and the independent variables, and develop an estimated regression equation that can be used to predict the Repair Time given Months Since Last Service, Type of Repair, and Repairperson.
b. What are the estimates for parameters of the independent variables?
c. What are the p-values of the t tests for the independent variables?
d. What is the p-value of the F test?
e. At the .05 level, are there significant relationship between the dependent variable and the independent variables?
f. What is the multiple coefficient of determination?
g. What is the adjusted multiple coefficient of determination?
h. Interpret the results.