In a study of poisons and treatments, three poisons and four treatments were used,
and four measurements were made for each pairing of a poison and a treatment.  
(So a crossed design was used, with four observations per cell.)  The observations
are the survival times for animals given a poison and a treatment.  (The shorter 
the survival time, the more effective the poison.  The longer the survival time, 
the more effective the treatment.  (Note: With a long enough survival time there 
might be adequate time for more effective life-saving measures to be undertaken.))

The survival times (in 10 hour units) are listed in the table below.


                      Treatment

                A      B      C      D

              0.31   0.82   0.43   0.45
              0.45   1.10   0.45   0.71
          I   0.46   0.88   0.63   0.66
              0.43   0.72   0.76   0.62

              0.36   0.92   0.44   0.56
Poison        0.29   0.61   0.35   1.02
         II   0.40   0.49   0.31   0.71
              0.23   1.24   0.40   0.38

              0.22   0.30   0.23   0.30
              0.21   0.37   0.25   0.36
        III   0.18   0.38   0.24   0.31
              0.23   0.29   0.22   0.33