* Test data from the book.
Coefficient  Estimate    St. Error 

      a       -8.73          5.62
      b(1)     1.27          0.35
      b(2)     0.93          0.48

Source              SS       DF         MS
Regression         28.27     2  14.13
Residual            1.73     1   0.87


Observed    Fitted     Residual

     4.00     4.40    -0.40
     7.00     6.33     0.67
     5.00     4.80     0.20
     8.00     8.93    -0.93
    11.00    10.53     0.47