Figure 3.

The f_i functions (as given by Eq. 1; i = 1, . . . , d) for the hare series (H2) with d = 3 (A) and the lynx series (L10) with d = 2 (B). See the main text for interpretation. All f_i functions have been smoothed by natural cubic splines with 2 degrees of freedom using the backfitting algorithm implemented in the function generalized additive models in s-plus (50). Estimated confidence intervals and residuals are also shown.