Question

PLEASE SHOW HOW TO SOLVE IN EXCEL SHOW STEPS

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	Repairperson
2.9	2	Electrical	Dave Newton
3	6	Mechanical	Dave Newton
4.8	8	Electrical	Bob Jones
1.8	3	Mechanical	Dave Newton
2.9	2	Electrical	Dave 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	Dave Newton

1. Ignore for now the months since the last maintenance service (x₁) and the repairperson who performed the service. Develop the estimated simple linear regression equation to predict the repair time (y) given the type of repair (x₂). Recall that x₂ = 0 if the type of repair is mechanical and 1 if the type of repair is electrical.
2. Does the equation that you developed in part (a) provide a good fit for the observed data? Explain.
3. Ignore for now the months since the last maintenance service and the type of repair associated with the machine. Develop the estimated simple linear regression equation to predict the repair time given the repairperson who performed the service. Let x₃ = 0 if Bob Jones performed the service and x₃ = 1 if Dave Newton performed the service.
4. Does the equation that you developed in part (c) provide a good fit for the observed data? Explain.
5. Develop the estimated regression equation to predict the repair time given the number of months since the last maintenance service, the type of repair, and the repairperson who performed the service.
6. At the .05 level of significance, test whether the estimated regression equation developed in part (e) represents a significant relationship between the independent variables and the dependent variable.
7. Is the addition of the independent variable x₃, the repairperson who performed the service, statistically significant? Use α = .05. What explanation can you give for the results observed?

Answer 1