Returns the age-specific fertility rate for age interval [Age,Age+AgeInterval). If AgeInterval is not specified it defaults to 1.0. In terms of the instantaneous fertility rate \(f(x)\) the fertility rate \(_n f_x\) from Age \(x\) for AgeInterval \(n\) is $$ _n f_x = \frac{1}{n}\int_x^{x+n} f(a) da $$
|