Homework SourseNote You must change the data table by X2 0 for mechanical
Note: You must change the data table by X2 = 0 (for mechanical) and X2 =1 (for electrical), and also X3 = 0 (for Bob Jones) and X3 =1 (for Dave Newton) BEFORE running regression! Use alpha = 0.05
a. Develop the Regression equation
b. How much of the variation in Satisfaction is explained by the variation in the independent variables ( Adjusted Coefficient of Determination)?
| Repair Time in Hours (Y) | Months Since Last Service (X2) | Type of Repair (X2) | Repairperson (X3) |
| 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 |
Solution
I have done this using minitab. steps are listed here
1) Enter the data in worksheet
2) Go to Stat
3) Select Regression
4) Select Fit regression model
5) put Y in \"responses\"
6) X1=Months Since Last Service in \"continuous predictors\"
7)X2=Type of Repair and X3= Repairperson in categorical covariates
click ok.
The adjusted R-squared is 85.03% this is the amount of variation explained.
Since we have 2 categorical variables X2 and X3 we wil have 4 regression equations (for the pairs (X2,X3)= (1,1),(0,0),(1,0),(0,1)
Regression Equation
X2 X3
0 0 Y = 1.860 + 0.2914 X1
0 1 Y = 1.251 + 0.2914 X1
1 0 Y = 2.963 + 0.2914 X1
