* Reference: Chapter 13 of
* Jeffrey M. Wooldridge, Introductory Econometrics: A Modern Approach,
* South-Western College Publishing, 2000.
SAMPLE 1 321
READ (KIELMC.shd) year age agesq nbh cbd intst lintst price rooms &
 area land baths dist ldist wind lprice y81 larea lland y81ldist &
 lintstsq nearinc y81nrinc rprice lrprice 

* Example 13.3, pp. 414-417
* The data set is arranged with all data for 1978 (179 observations),
* followed by all data for 1981. 

* Rescale the price variable to express house prices in thousands
* of dollars.
GENR rprice = rprice / 1000

* House price equation for 1981 - Equation (13.4), p. 415.
SAMPLE 180 321
OLS rprice nearinc
* Note that the rescaling of the price variable has resulted in 
* a rescaling of the estimated coefficients.

* House price equation for 1978 - Equation (13.5), p. 415.
SAMPLE 1 179
OLS rprice nearinc

* Separate regressions for each year can be obtained from a
* pooled regression that incorporates dummy variables.
SAMPLE 1 321
* Estimation results in column (1) of Table 13.2, p. 416
OLS rprice y81 nearinc y81nrinc    
* Estimation results in column (2) of Table 13.2, p. 416
OLS rprice y81 nearinc y81nrinc age agesq   
* Estimation results in column (3) of Table 13.2, p. 416
OLS rprice y81 nearinc y81nrinc age agesq intst land area rooms baths

* Now consider a log-transformed dependent variable
* Equation (13-9), p. 417
OLS lprice y81 nearinc y81nrinc    
OLS lprice y81 nearinc y81nrinc age agesq lintst lland larea rooms baths
STOP