TABLE 9

Effects of variance in γ on estimates of mean γ Embedded Image

αβγ̅σγγ̅approxγ̅normal
 0 2.50 0.002.502.50
20 0.13 2.57 0.562.592.60
10 0.26 2.64 0.842.722.65
 5 0.56 2.82 1.263.022.87
 2 1.85 3.71 2.624.19
 1 4.79 4.79 4.795.55
 0.523.0011.3016.308.38
  • The first four columns relate to a gamma distribution of the scaled selection intensity γ; the fifth gives the estimate of mean γ obtained for a general distribution from the second-order Taylor series approximation, with the same variance as the gamma distribution; the sixth is the estimate for a normal distribution with this variance. See text for further details.