Parameter estimates using different the sex-ratios (Female∶Male) reported in Canada over the period from 1931 to 1980^*.

Values derived from reference [65] for the condition where (C = 0.5) and assuming the change in the environmental factor (whatever this is) has been steadily increasing (i.e., linear) over the time-interval (sd = standard deviation). The estimates for the parameters a and b trend downward in the more recent time-intervals because the definition of a unit of environmental change (see Table 2) becomes smaller with more recent observation periods. The other estimates are unaffected by this circumstance (see Equations 14, 17, and 21).

Values for the maximum value that C could take (see text); extrapolated backward to the (1941–1945) time-period for comparison.