Chapter 16: Results of an experiment with three controlled
factors.

Col 1: Level of factor A.
Col 2: Level of factor B.
Col 3: Level of factor C.
Cols 4-7: Observed values.
Col 8: average.
Col 9: variance.
Col 10: logarithm, to the base 10, of the variance.
          
-    -    -     60.5  61.7  60.5  60.8    60.875  0.323  -0.491
+    -    -     47.0  46.3  46.7  47.2    46.800  0.153  -0.814
-    +    -     92.1  91.0  92.0  91.6    91.675  0.249  -0.604
+    +    -     71.0  71.7  71.1  70.0    70.950  0.497  -0.304
-    -    +     65.2  66.8  64.3  65.2    65.375  1.083   0.034
+    -    +     49.5  50.6  49.5  50.5    50.025  0.369  -0.433
-    +    +     91.2  90.5  91.5  88.7    90.475  1.576   0.198
+    +    +     76.0  76.0  78.3  76.4    76.675  1.209   0.082