options double crt;
name hedo1 'Hedonic data - 1-way ML estimates';
?  Source: Harrison and Rubinfeld (1978). See also
?          Belsley, Kuh and Welsch (1980).
?  Description: Cross-Section, 506 Census tracts in the Boston area in 1970.
?  Variables:
doc MV    'Medium value of owner-occupied homes';
doc CRIM  'Crime rate';
doc ZN    'Proportion of 25,000 square feet residential lots';
doc INDUS 'Proportion of nonretail business acres'; 
doc CHAS  'dummy variable which is 1 if the tract bounds the Charles River'; 
doc NOX
 'Annual average nitrogen oxide concentration in parts per hundred million';  
doc RM  'Average number of rooms';
doc AGE 'Proportion of owner units built prior to 1940';
doc DIS 'Weighted distances to five employment centers in the Boston area';
doc RAD 'Index of accessibility to radial highways';
doc TAX 'Full value property tax rate ($/$10,000)';
doc PTRATIO 'Pupil / teacher ratio';
doc B      'Proportion of blacks in the population';
doc LSTAT  'Proportion of population that is lower status';
doc TOWNID 'Town identifier'; 
list vars MV CRIM ZN INDUS CHAS NOX RM AGE DIS RAD TAX PTRATIO B LSTAT TOWNID;
set n=92;
set nt=506;
smpl 1,nt;
read(file='hedonic.txt') vars;
freq(panel,id=TOWNID);

? rescale variables to match Baltagi table 9.1
CRIM = CRIM/100;
ZN   = ZN  /1000;
INDUS = INDUS/100;
CHAS = CHAS/10 ;
NOX  = NOX /100;
RM   = RM  /100;
AGE  = AGE /1000;
DIS  = DIS /10 ;
RAD  = RAD /10 ;
TAX  = TAX /1000;
PTRATIO = PTRATIO/100;
LSTAT = LSTAT/10 ;

title 'one-way ML: Baltagi(2001) p.168';
list yx MV CRIM ZN INDUS CHAS NOX RM AGE DIS RAD TAX PTRATIO B LSTAT;
panel(rei,tol=1e-7) yx;

? Note:  s2v = S2_IT ,  s2mu = S2_I