*
* CHAPTER 9
* Page 332
*
open data ch09_mcas.xls
data(format=xls,org=columns) 1 220 code regday specneed bilingua occupday tot_day $
 s_p_c spec_ed lnch_pct tchratio percap totsc4 totsc8 avgsalry pctel
*
table / totsc4 tchratio pctel lnch_pct percap
*
set lpercap    = log(percap)
set percap2    = percap**2
set percap3    = percap**3
set tchratio2  = tchratio**2
set tchratio3  = tchratio**3
*
* HIEL is defined to be a dummy indicating whether the percentage of English
* learners is greater than the median. This will create that. Note, though, that
* in this case, the median is 0, so it will just be a dummy for a positive value.
*
stats(fractiles) pctel
set hiel       = pctel>%median
set strxhiel   = tchratio*hiel
*
*
* Table 9.2
*
* Column 1
*
linreg(robust) totsc4
# tchratio constant
*
* Column 2
*
linreg(robust) totsc4
# tchratio pctel lnch_pct lpercap constant
*
* Column 3
*
linreg(robust) totsc4
# tchratio pctel lnch_pct percap percap2 percap3 constant
*
* Column 4
*
linreg(robust) totsc4
# tchratio tchratio2 tchratio3 pctel lnch_pct percap percap2 percap3 constant
*
* Column 5
*
linreg(robust) totsc4
# tchratio hiel strxhiel lnch_pct percap percap2 percap3 constant
*
* Column 6
*
linreg(robust) totsc4
# tchratio lnch_pct percap percap2 percap3 constant