* Chapter 14 - Models for Panel Data
* W.H. Greene, Econometric Analysis, Fourth Edition, 2000.
SAMPLE 1 90
READ (airline.shd) / NAMES

* Example 14.1, p. 559
GENR LC=LOG(C)
GENR LQ=LOG(Q)
GENR LPF=LOG(PF)
OLS LC LQ LPF LF 
* Estimate the economies of scale (formula on p. 558)
TEST 1/LQ - 1

* Alternatively - the above results can be produced with the POOL command.
*   - The number of cross-section units must be specified with the 
*     NCROSS= option.
*   - The OLS option is used for pooling by OLS.
POOL LC LQ LPF LF / NCROSS=6 OLS
TEST 1/LQ - 1
GEN1 RR=$R2

* Example 14.2 - Fixed Effects Regressions, pp. 565-566.
POOL LC LQ LPF LF / NCROSS=6 OLS FIXED
GEN1 RU=$R2    
*  Test the significance of the group effects.
*  Calculate the F-test statistic using the calculation method at the 
*  bottom of p. 565.
GEN1 F=((RU-RR)/5)/((1-RU)/81)
PRINT F
* The textbook calculation of the F-test statistic has some rounding 
* error -- SHAZAM retains more decimal places in the calculation.
STOP