Tutor-marked Exercise 4: Computer Section

Running head: TUTOR-MARKED EXERCISE 4: COMPUTER SECTION
Tutor-marked Exercise 4: Computer Section
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TUTOR-MARKED EXERCISE 4: COMPUTER SECTION
Table of Contents
Answer 1....................................................................................................................................3
Answer 1. A. Matrix plot.......................................................................................................3
Answer 1. B. Histogram and a normal probability plot.........................................................3
Answer 1. C. Violated assumption of regression...................................................................6
Answer 1. D. Regression equation.........................................................................................6
Answer 1. E. Standard error...................................................................................................8
Answer 1. F. Coefficient of determination.............................................................................9
Answer 1. G. Coefficient of determination adjusted to degrees of freedom..........................9
Answer 1. H. Validity of the model.......................................................................................9
Answer 1. I. Interpretation of each coefficients...................................................................10
Answer 1. J. Linear relation between independent variable and dependent variable..........11
Answer 1. K. Step-wise regression......................................................................................12
Answer 1. L. Excluded variables.........................................................................................13
Reference..................................................................................................................................14
Appendices...............................................................................................................................15
Appendix 1...........................................................................................................................15
Appendix 2...........................................................................................................................16
Appendix 3...........................................................................................................................17
Appendix 4...........................................................................................................................20
Appendix 5...........................................................................................................................25
Appendix 6...........................................................................................................................27

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TUTOR-MARKED EXERCISE 4: COMPUTER SECTION
Appendix 7...........................................................................................................................28
Appendix 8...........................................................................................................................29

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TUTOR-MARKED EXERCISE 4: COMPUTER SECTION
Answer 1
Answer 1. A. Matrix plot
The first column of the matrix plot shows the relation of Y with X1, X2, X3, X4 and X5.
The scatter plots are linear except for the relation Y against X5. That means there exists a
linear relation between Y and other independent variables except X5.
Answer 1. B. Histogram and a normal probability plot

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TUTOR-MARKED EXERCISE 4: COMPUTER SECTION

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TUTOR-MARKED EXERCISE 4: COMPUTER SECTION

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TUTOR-MARKED EXERCISE 4: COMPUTER SECTION
Answer 1. C. Violated assumption of regression
The residual is not normally distributed which is an important assumption. The
histogram shows that the assumption of normality is violated.
Answer 1. D. Regression equation

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TUTOR-MARKED EXERCISE 4: COMPUTER SECTION