The data set SALES contains weekly information on the sales of refrigerators and stoves by two sales representatives. 
data sales;
   input Month Week Seller $ Icebox Stove;
   datalines;
1 1 Kreitz   3450.94 1312.61
1 1 LeGrange 2520.04  728.13
1 2 Kreitz   3240.67  222.35
1 2 LeGrange 2675.42  184.24
1 3 Kreitz   3160.45 2263.33
1 3 LeGrange 2805.35  267.35
1 4 Kreitz   3400.24 1787.45
1 4 LeGrange 2870.61  274.51
2 1 Kreitz   3550.43 2910.37
2 1 LeGrange 2730.09  397.98
2 2 Kreitz   3385.74  819.69
2 2 LeGrange 2670.93 2242.24
;