[Spambayes] There Can Be Only One

[Tim Peters]

Inspired by Neil and Anthony, I tried

robinson_probability_a: 0.225

in my test case.  It made no difference to results, but separated the ham
and spam means at the cost of increasing their variances (a=0.5 vs a=0.225
here):


ham mean                     ham sdev
  33.01   32.00   -3.06%        6.26    6.39   +2.08%
  32.19   31.14   -3.26%        5.38    5.51   +2.42%
  32.99   31.96   -3.12%        5.60    5.71   +1.96%
  33.46   32.46   -2.99%        5.77    5.90   +2.25%
  33.16   32.20   -2.90%        5.56    5.74   +3.24%
  32.81   31.85   -2.93%        5.72    5.81   +1.57%
  33.38   32.36   -3.06%        5.76    5.89   +2.26%
  32.55   31.51   -3.20%        5.70    5.91   +3.68%
  33.11   32.14   -2.93%        5.52    5.63   +1.99%
  34.21   33.22   -2.89%        5.84    5.95   +1.88%

ham mean and sdev for all runs
  33.09   32.09   -3.02%        5.73    5.87   +2.44%

spam mean                    spam sdev
  82.95   83.89   +1.13%        6.82    7.16   +4.99%
  82.17   83.11   +1.14%        6.34    6.85   +8.04%
  82.06   83.08   +1.24%        6.14    6.58   +7.17%
  82.39   83.20   +0.98%        5.93    6.31   +6.41%
  82.53   83.31   +0.95%        7.00    7.33   +4.71%
  82.76   83.76   +1.21%        6.56    7.01   +6.86%
  82.06   82.97   +1.11%        5.73    6.02   +5.06%
  82.26   83.09   +1.01%        5.97    6.17   +3.35%
  82.65   83.55   +1.09%        6.71    7.07   +5.37%
  83.43   84.37   +1.13%        6.37    6.71   +5.34%

spam mean and sdev for all runs
  82.53   83.43   +1.09%        6.37    6.75   +5.97%

ham/spam mean difference: 49.44 51.34 +1.90

I can live with that.

In contrast, Skip reported a ham mean of 22.67 (much lower) with sdev 7.57
(higher), and a spam mean of 69.27 (much lower) with sdev 12.38 (much
higher).  His spam and his ham are hammier, but less certain of themselves.
I expect talk therapy would do them some good <wink>.