Chapter 12: Averages and ranges for measurements of a dimension
of molded plastic rheostat knobs.

Col 1: Hour.
Col 2: Average (in units of 0.001 inches).
Col 3: Range (in units of 0.001 inches).

     1    137.8      9
     2    143.0      8
     3    141.2     15
     4    139.8      6
     5    140.0     10
     6    139.2      8
     7    141.2     10
     8    140.0      8
     9    142.0      7
    10    139.2     13
    11    139.6     12
    12    141.4      9
    13    141.2      3
    14    140.6      8
    15    141.6      9
    16    140.4     13
    17    140.0      6
    18    141.8      8
    19    140.4      8
    20    138.8      6