Reporting Results, and choosing a functional form. Hill et al chapter 6.
Explained and Unexplained Variation Total Explained Unexplained
Decomposing the variation link to proof
Coefficient of determination
Example
Reporting Results
Choosing a functional form Model has been assumed to be linear in the parameters. Linear in parameters: parameters are not multiplied together, raised to a power etc. variables, however, can be transformed in any convenient way, as long as the resulting model satisfies assumptions SR1- SR5 of the simple linear regression model.
A functional form for food expenditure It is expected that food expenditure will rise at a decreasing rate with income
Some common functional forms
Empirical issues
An alternative functional form
Are the residuals normal (Jarque- Bera)
Appendix: proof back