/* iowacorn1.sas */
options ls=72 ps=60;
data iowacorn;
   infile 'iowacorn.dat';
   input x1 x2 x3 x4 x5 x6 x7 x8 x9 y;
/* coding
   x1 = year
   x2 = precip1
   x3 = maytemp
   x4 = junerain
   x5 = junetemp
   x6 = julyrain
   x7 = julytemp
   x8 = augrain
   x9 = augtemp
   y = yield     */
proc print;
title 'iowacorn data';
proc plot data=iowacorn;
   plot y*x1 y*x2 y*x3 y*x4 y*x5 y*x6 y*x7 y*x8 y*x9
        x1*x2 x1*x3 x1*x4 x1*x5 x1*x6 x1*x7 x1*x8 x1*x9
        x2*x3 x2*x4 x2*x5 x2*x6 x2*x7 x2*x8 x2*x9
        x3*x4 x3*x5 x3*x6 x3*x7 x3*x8 x3*x9
        x4*x5 x4*x6 x4*x7 x4*x8 x4*x9
        x5*x6 x5*x7 x5*x8 x5*x9
        x6*x7 x6*x8 x6*x9
        x7*x8 x7*x9
        x8*x9;
proc reg data=iowacorn;
   model y = x1-x9;
      output out=fullfit p=yhat r=resid;
title 'full model with all variables';
proc plot data=fullfit;
   plot resid*yhat / vref=0;
proc reg data=iowacorn;
   model y = x1-x9 / include=1 selection=rsquare adjrsq cp aic sbc;
title 'all possible regressions forcing x1 to be included';
proc reg data=iowacorn;
   model y = x1 /noprint;
      output out=new1 press=pressresid;
   model y = x1 x2 /noprint;
      output out=new12 press=pressresid;
   model y = x1 x3 /noprint;
      output out=new13 press=pressresid;
   model y = x1 x4 /noprint;
      output out=new14 press=pressresid;
   model y = x1 x5 /noprint;
      output out=new15 press=pressresid;
   model y = x1 x6 /noprint;
      output out=new16 press=pressresid;
   model y = x1 x7 /noprint;
      output out=new17 press=pressresid;
   model y = x1 x8 /noprint;
      output out=new18 press=pressresid;
   model y = x1 x9 /noprint;
      output out=new19 press=pressresid;
   model y = x1 x2 x3 /noprint;
      output out=new123 press=pressresid;
   model y = x1 x2 x4 /noprint;
      output out=new124 press=pressresid;
   model y = x1 x2 x5 /noprint;
      output out=new125 press=pressresid;
   model y = x1 x2 x6 /noprint;
      output out=new126 press=pressresid;
   model y = x1 x2 x7 /noprint;
      output out=new127 press=pressresid;
   model y = x1 x2 x8 /noprint;
      output out=new128 press=pressresid;
   model y = x1 x2 x9 /noprint;
      output out=new129 press=pressresid;
   model y = x1 x3 x4 /noprint;
      output out=new134 press=pressresid;
   model y = x1 x3 x5 /noprint;
      output out=new135 press=pressresid;
   model y = x1 x3 x6 /noprint;
      output out=new136 press=pressresid;
   model y = x1 x3 x7 /noprint;
      output out=new137 press=pressresid;
   model y = x1 x3 x8 /noprint;
      output out=new138 press=pressresid;
   model y = x1 x3 x9 /noprint;
      output out=new139 press=pressresid;
   model y = x1 x4 x5 /noprint;
      output out=new145 press=pressresid;
   model y = x1 x4 x6 /noprint;
      output out=new146 press=pressresid;
   model y = x1 x4 x7 /noprint;
      output out=new147 press=pressresid;
   model y = x1 x4 x8 /noprint;
      output out=new148 press=pressresid;
   model y = x1 x4 x9 /noprint;
      output out=new149 press=pressresid;
   model y = x1 x5 x6 /noprint;
      output out=new156 press=pressresid;
   model y = x1 x5 x7 /noprint;
      output out=new157 press=pressresid;
   model y = x1 x5 x8 /noprint;
      output out=new158 press=pressresid;
   model y = x1 x5 x9 /noprint;
      output out=new159 press=pressresid;
   model y = x1 x6 x7 /noprint;
      output out=new167 press=pressresid;
   model y = x1 x6 x8 /noprint;
      output out=new168 press=pressresid;
   model y = x1 x6 x9 /noprint;
      output out=new169 press=pressresid;
   model y = x1 x7 x8 /noprint;
      output out=new178 press=pressresid;
   model y = x1 x7 x9 /noprint;
      output out=new179 press=pressresid;
   model y = x1 x8 x9 /noprint;
      output out=new189 press=pressresid;
   model y = x1 x2 x3 x4 /noprint;
      output out=new1234 press=pressresid;
   model y = x1 x2 x3 x5 /noprint;
      output out=new1235 press=pressresid;
   model y = x1 x2 x3 x6 /noprint;
      output out=new1236 press=pressresid;
   model y = x1 x2 x3 x7 /noprint;
      output out=new1237 press=pressresid;
   model y = x1 x2 x3 x8 /noprint;
      output out=new1238 press=pressresid;
   model y = x1 x2 x3 x9 /noprint;
      output out=new1239 press=pressresid;
   model y = x1 x2 x4 x5 /noprint;
      output out=new1245 press=pressresid;
   model y = x1 x2 x4 x6 /noprint;
      output out=new1246 press=pressresid;
   model y = x1 x2 x4 x7 /noprint;
      output out=new1247 press=pressresid;
   model y = x1 x2 x4 x8 /noprint;
      output out=new1248 press=pressresid;
   model y = x1 x2 x4 x9 /noprint;
      output out=new1249 press=pressresid;
   model y = x1 x2 x5 x6 /noprint;
      output out=new1256 press=pressresid;
   model y = x1 x2 x5 x7 /noprint;
      output out=new1257 press=pressresid;
   model y = x1 x2 x5 x8 /noprint;
      output out=new1258 press=pressresid;
   model y = x1 x2 x5 x9 /noprint;
      output out=new1259 press=pressresid;
   model y = x1 x2 x6 x7 /noprint;
      output out=new1267 press=pressresid;
   model y = x1 x2 x6 x8 /noprint;
      output out=new1268 press=pressresid;
   model y = x1 x2 x6 x9 /noprint;
      output out=new1269 press=pressresid;
   model y = x1 x2 x7 x8 /noprint;
      output out=new1278 press=pressresid;
   model y = x1 x2 x7 x9 /noprint;
      output out=new1279 press=pressresid;
   model y = x1 x2 x8 x9 /noprint;
      output out=new1289 press=pressresid;
   model y = x1 x3 x4 x5 /noprint;
      output out=new1345 press=pressresid;
   model y = x1 x3 x4 x6 /noprint;
      output out=new1346 press=pressresid;
   model y = x1 x3 x4 x7 /noprint;
      output out=new1347 press=pressresid;
   model y = x1 x3 x4 x8 /noprint;
      output out=new1348 press=pressresid;
   model y = x1 x3 x4 x9 /noprint;
      output out=new1349 press=pressresid;
   model y = x1 x3 x5 x6 /noprint;
      output out=new1356 press=pressresid;
   model y = x1 x3 x5 x7 /noprint;
      output out=new1357 press=pressresid;
   model y = x1 x3 x5 x8 /noprint;
      output out=new1358 press=pressresid;
   model y = x1 x3 x5 x9 /noprint;
      output out=new1359 press=pressresid;
   model y = x1 x3 x6 x7 /noprint;
      output out=new1367 press=pressresid;
   model y = x1 x3 x6 x8 /noprint;
      output out=new1368 press=pressresid;
   model y = x1 x3 x6 x9 /noprint;
      output out=new1369 press=pressresid;
   model y = x1 x3 x7 x8 /noprint;
      output out=new1378 press=pressresid;
   model y = x1 x3 x7 x9 /noprint;
      output out=new1379 press=pressresid;
   model y = x1 x3 x8 x9 /noprint;
      output out=new1389 press=pressresid;
   model y = x1 x4 x5 x6 /noprint;
      output out=new1456 press=pressresid;
   model y = x1 x4 x5 x7 /noprint;
      output out=new1457 press=pressresid;
   model y = x1 x4 x5 x8 /noprint;
      output out=new1458 press=pressresid;
   model y = x1 x4 x5 x9 /noprint;
      output out=new1459 press=pressresid;
   model y = x1 x4 x6 x7 /noprint;
      output out=new1467 press=pressresid;
   model y = x1 x4 x6 x8 /noprint;
      output out=new1468 press=pressresid;
   model y = x1 x4 x6 x9 /noprint;
      output out=new1469 press=pressresid;
   model y = x1 x4 x7 x8 /noprint;
      output out=new1478 press=pressresid;
   model y = x1 x4 x7 x9 /noprint;
      output out=new1479 press=pressresid;
   model y = x1 x4 x8 x9 /noprint;
      output out=new1489 press=pressresid;
   model y = x1 x5 x6 x7 /noprint;
      output out=new1567 press=pressresid;
   model y = x1 x5 x6 x8 /noprint;
      output out=new1568 press=pressresid;
   model y = x1 x5 x6 x9 /noprint;
      output out=new1569 press=pressresid;
   model y = x1 x5 x7 x8 /noprint;
      output out=new1578 press=pressresid;
   model y = x1 x5 x7 x9 /noprint;
      output out=new1579 press=pressresid;
   model y = x1 x5 x8 x9 /noprint;
      output out=new1589 press=pressresid;
   model y = x1 x6 x7 x8 /noprint;
      output out=new1678 press=pressresid;
   model y = x1 x6 x7 x9 /noprint;
      output out=new1679 press=pressresid;
   model y = x1 x6 x8 x9 /noprint;
      output out=new1689 press=pressresid;
   model y = x1 x7 x8 x9 /noprint;
      output out=new1789 press=pressresid;
proc means data=new1 noprint;
   var pressresid;
   output out=new1a uss=press;
proc means data=new12 noprint;
   var pressresid;
   output out=new12a uss=press;
proc means data=new13 noprint;
   var pressresid;
   output out=new13a uss=press;
proc means data=new14 noprint;
   var pressresid;
   output out=new14a uss=press;
proc means data=new15 noprint;
   var pressresid;
   output out=new15a uss=press;
proc means data=new16 noprint;
   var pressresid;
   output out=new16a uss=press;
proc means data=new17 noprint;
   var pressresid;
   output out=new17a uss=press;
proc means data=new18 noprint;
   var pressresid;
   output out=new18a uss=press;
proc means data=new19 noprint;
   var pressresid;
   output out=new19a uss=press;
proc means data=new123 noprint;
   var pressresid;
   output out=new123a uss=press;
proc means data=new124 noprint;
   var pressresid;
   output out=new124a uss=press;
proc means data=new125 noprint;
   var pressresid;
   output out=new125a uss=press;
proc means data=new126 noprint;
   var pressresid;
   output out=new126a uss=press;
proc means data=new127 noprint;
   var pressresid;
   output out=new127a uss=press;
proc means data=new128 noprint;
   var pressresid;
   output out=new128a uss=press;
proc means data=new129 noprint;
   var pressresid;
   output out=new129a uss=press;
proc means data=new134 noprint;
   var pressresid;
   output out=new134a uss=press;
proc means data=new135 noprint;
   var pressresid;
   output out=new135a uss=press;
proc means data=new136 noprint;
   var pressresid;
   output out=new136a uss=press;
proc means data=new137 noprint;
   var pressresid;
   output out=new137a uss=press;
proc means data=new138 noprint;
   var pressresid;
   output out=new138a uss=press;
proc means data=new139 noprint;
   var pressresid;
   output out=new139a uss=press;
proc means data=new145 noprint;
   var pressresid;
   output out=new145a uss=press;
proc means data=new146 noprint;
   var pressresid;
   output out=new146a uss=press;
proc means data=new147 noprint;
   var pressresid;
   output out=new147a uss=press;
proc means data=new148 noprint;
   var pressresid;
   output out=new148a uss=press;
proc means data=new149 noprint;
   var pressresid;
   output out=new149a uss=press;
proc means data=new156 noprint;
   var pressresid;
   output out=new156a uss=press;
proc means data=new157 noprint;
   var pressresid;
   output out=new157a uss=press;
proc means data=new158 noprint;
   var pressresid;
   output out=new158a uss=press;
proc means data=new159 noprint;
   var pressresid;
   output out=new159a uss=press;
proc means data=new167 noprint;
   var pressresid;
   output out=new167a uss=press;
proc means data=new168 noprint;
   var pressresid;
   output out=new168a uss=press;
proc means data=new169 noprint;
   var pressresid;
   output out=new169a uss=press;
proc means data=new178 noprint;
   var pressresid;
   output out=new178a uss=press;
proc means data=new179 noprint;
   var pressresid;
   output out=new179a uss=press;
proc means data=new189 noprint;
   var pressresid;
   output out=new189a uss=press;
proc means data=new1234 noprint;
   var pressresid;
   output out=new1234a uss=press;
proc means data=new1235 noprint;
   var pressresid;
   output out=new1235a uss=press;
proc means data=new1236 noprint;
   var pressresid;
   output out=new1236a uss=press;
proc means data=new1237 noprint;
   var pressresid;
   output out=new1237a uss=press;
proc means data=new1238 noprint;
   var pressresid;
   output out=new1238a uss=press;
proc means data=new1239 noprint;
   var pressresid;
   output out=new1239a uss=press;
proc means data=new1245 noprint;
   var pressresid;
   output out=new1245a uss=press;
proc means data=new1246 noprint;
   var pressresid;
   output out=new1246a uss=press;
proc means data=new1247 noprint;
   var pressresid;
   output out=new1247a uss=press;
proc means data=new1248 noprint;
   var pressresid;
   output out=new1248a uss=press;
proc means data=new1249 noprint;
   var pressresid;
   output out=new1249a uss=press;
proc means data=new1256 noprint;
   var pressresid;
   output out=new1256a uss=press;
proc means data=new1257 noprint;
   var pressresid;
   output out=new1257a uss=press;
proc means data=new1258 noprint;
   var pressresid;
   output out=new1258a uss=press;
proc means data=new1259 noprint;
   var pressresid;
   output out=new1259a uss=press;
proc means data=new1267 noprint;
   var pressresid;
   output out=new1267a uss=press;
proc means data=new1268 noprint;
   var pressresid;
   output out=new1268a uss=press;
proc means data=new1269 noprint;
   var pressresid;
   output out=new1269a uss=press;
proc means data=new1278 noprint;
   var pressresid;
   output out=new1278a uss=press;
proc means data=new1279 noprint;
   var pressresid;
   output out=new1279a uss=press;
proc means data=new1289 noprint;
   var pressresid;
   output out=new1289a uss=press;
proc means data=new1345 noprint;
   var pressresid;
   output out=new1345a uss=press;
proc means data=new1346 noprint;
   var pressresid;
   output out=new1346a uss=press;
proc means data=new1347 noprint;
   var pressresid;
   output out=new1347a uss=press;
proc means data=new1348 noprint;
   var pressresid;
   output out=new1348a uss=press;
proc means data=new1349 noprint;
   var pressresid;
   output out=new1349a uss=press;
proc means data=new1356 noprint;
   var pressresid;
   output out=new1356a uss=press;
proc means data=new1357 noprint;
   var pressresid;
   output out=new1357a uss=press;
proc means data=new1358 noprint;
   var pressresid;
   output out=new1358a uss=press;
proc means data=new1359 noprint;
   var pressresid;
   output out=new1359a uss=press;
proc means data=new1367 noprint;
   var pressresid;
   output out=new1367a uss=press;
proc means data=new1368 noprint;
   var pressresid;
   output out=new1368a uss=press;
proc means data=new1369 noprint;
   var pressresid;
   output out=new1369a uss=press;
proc means data=new1378 noprint;
   var pressresid;
   output out=new1378a uss=press;
proc means data=new1379 noprint;
   var pressresid;
   output out=new1379a uss=press;
proc means data=new1389 noprint;
   var pressresid;
   output out=new1389a uss=press;
proc means data=new1456 noprint;
   var pressresid;
   output out=new1456a uss=press;
proc means data=new1457 noprint;
   var pressresid;
   output out=new1457a uss=press;
proc means data=new1458 noprint;
   var pressresid;
   output out=new1458a uss=press;
proc means data=new1459 noprint;
   var pressresid;
   output out=new1459a uss=press;
proc means data=new1467 noprint;
   var pressresid;
   output out=new1467a uss=press;
proc means data=new1468 noprint;
   var pressresid;
   output out=new1468a uss=press;
proc means data=new1469 noprint;
   var pressresid;
   output out=new1469a uss=press;
proc means data=new1478 noprint;
   var pressresid;
   output out=new1478a uss=press;
proc means data=new1479 noprint;
   var pressresid;
   output out=new1479a uss=press;
proc means data=new1489 noprint;
   var pressresid;
   output out=new1489a uss=press;
proc means data=new1567 noprint;
   var pressresid;
   output out=new1567a uss=press;
proc means data=new1568 noprint;
   var pressresid;
   output out=new1568a uss=press;
proc means data=new1569 noprint;
   var pressresid;
   output out=new1569a uss=press;
proc means data=new1578 noprint;
   var pressresid;
   output out=new1578a uss=press;
proc means data=new1579 noprint;
   var pressresid;
   output out=new1579a uss=press;
proc means data=new1589 noprint;
   var pressresid;
   output out=new1589a uss=press;
proc means data=new1678 noprint;
   var pressresid;
   output out=new1678a uss=press;
proc means data=new1679 noprint;
   var pressresid;
   output out=new1679a uss=press;
proc means data=new1689 noprint;
   var pressresid;
   output out=new1689a uss=press;
proc means data=new1789 noprint;
   var pressresid;
   output out=new1789a uss=press;
data press1;
   set new1a     new12a    new13a    new14a    new15a    new16a
       new17a    new18a    new19a    new123a   new124a   new125a
       new126a   new127a   new128a   new129a   new134a   new135a
       new136a   new137a   new138a   new139a   new145a   new146a
       new147a   new148a   new149a   new156a   new157a   new158a
       new159a   new167a   new168a   new169a   new178a   new179a
       new189a   new1234a  new1235a  new1236a  new1237a
       new1238a  new1239a  new1245a  new1246a  new1247a
       new1248a  new1249a  new1256a  new1257a  new1258a
       new1259a  new1267a  new1268a  new1269a  new1278a
       new1279a  new1289a  new1345a  new1346a  new1347a
       new1348a  new1349a  new1356a  new1357a  new1358a
       new1359a  new1367a  new1368a  new1369a
       new1378a  new1379a  new1389a  new1456a
       new1457a   new1458a   new1459a
       new1467a   new1468a   new1469a
       new1478a   new1479a   new1489a
       new1567a   new1568a   new1569a
       new1578a   new1579a   new1589a
       new1678a   new1679a   new1689a
       new1789a;
data labels;
   input model @@;
cards;
1 12 13 14 15 16 17 18 19
123 124 125 126 127 128 129
134 135 136 137 138 139
145 146 147 148 149
156 157 158 159
167 168 169
178 179
189
1234 1235 1236 1237 1238 1239
1245 1246 1247 1248 1249
1256 1257 1258 1259
1267 1268 1269
1278 1279
1289
1345 1346 1347 1348 1349
1356 1357 1358 1359
1367 1368 1369
1378 1379
1389
1456 1457 1458 1459
1467 1468 1469
1478 1479
1489
1567 1568 1569
1578 1579
1589
1678 1679
1689
1789
;
data press2;
   merge labels press1;
proc sort data=press2 out=press3;
   by press;
proc print data=press3;
   var model press;
title 'press selection forcing x1 to be included';
run;