* Machine Operator;

data machine;



machine    operator      y

----------------------------

   1           1       51.43

   1           1       51.28

   1           2       50.93

   1           2       50.75

   1           3       50.47

   1           3       50.83

   2           1       51.91

   2           1       52.43

   2           2       52.26

   2           2       52.33

   2           3       51.58

   2           3       51.23