options linesize=70 pagesize=50;

data a;
infile 'data.txt';
input  ravlchm hhinc black hslds setr vac indexr pstu 
         roadacc roadcap transacc transcap;

/* This is to define log transformations of the 4 predictors of interest*/

lra = log(roadacc+0.5);
lrc = log(roadcap+0.5);
lta = log(transacc+0.5);
ltc = log(transcap+0.5);

/* this is to define log transf of response */
lrav = log(ravlchm);
run;

/*  Model for the raw data */

proc reg data=a;
model  ravlchm = hhinc black hslds setr vac indexr pstu 
         roadacc roadcap transacc transcap  /P R COLLIN;;
output out=b p=pred r=res;

/*  Model for the raw response and the log of the 4 predictors */

proc reg data=a;
model  ravlchm = hhinc black hslds setr vac indexr pstu 
         lra lrc lta ltc /P R COLLIN;;
output out=b p=pred r=res;

/*  Model for the log response and the log of the 4 predictors */
proc reg data=a;
model  lrav = hhinc black hslds setr vac indexr pstu 
         lra lrc lta ltc /P R COLLIN;;
output out=b p=pred r=res;

/* To plot residuals in the above cases */

proc plot data=b;
plot res*pred res*( lra lrc lta ltc );
run;

/* to do the model selection for the second example*/

proc reg data=a;
model  lrav = hhinc black hslds setr vac indexr pstu 
            lra lrc lta ltc /selection=adjrsq;

/*  remember after model selection do the regression for the
    final model
*/