data one;
  input temp density salinity wg;
  cards;
25  80 10  86
25  80 10  52
25  80 10  73
25  80 25 544
25  80 25 371
25  80 25 482
25  80 40 390
25  80 40 290
25  80 40 397
25 160 10  53
25 160 10  73
25 160 10  86
25 160 25 393
25 160 25 398
25 160 25 208
25 160 40 249
25 160 40 265
25 160 40 243
35  80 10 439
35  80 10 436
35  80 10 349
35  80 25 249
35  80 25 245
35  80 25 330
35  80 40 247
35  80 40 277
35  80 40 205
35 160 10 324
35 160 10 305
35 160 10 364
35 160 25 352
35 160 25 267
35 160 25 316
35 160 40 188
35 160 40 223
35 160 40 281
;

proc glm;
  class temp density salinity;
  model wg=temp density salinity temp*density temp*salinity density*salinity
           temp*density*salinity;
  lsmeans temp / stderr;
  lsmeans density / stderr;
  lsmeans salinity / stderr;
  lsmeans temp*density / stderr;
  lsmeans temp*salinity / stderr;
  lsmeans density*salinity / stderr;
  lsmeans temp*density*salinity / stderr;
  lsmeans temp*density*salinity / slice=density*salinity;
  lsmeans temp*density*salinity / slice=temp*salinity;
  lsmeans temp*density*salinity / slice=temp*density;
run;