NOTE 19Q: We can also look at the variability in the data. The variance of allele frequency around the equilibrium in the last 50 generations is 0.0033 (i.e., a standard deviation of 0.058). The variance expected from sampling 100 diploid individuals, or 200 genes, is *pq*/2*N* = 0.39 × 0.41/200 = 0.00080, which is higher than this. Therefore, there is no evidence of any extra variation due to drift: The population has a large effective size.