Fig. 4.

Group average first-, second-, and third-order kernel estimates of reduced Uryson models of the total arc for WKY, SHR₁₂₀, and SHR₁₆₀ via the frequency-domain method for Gaussian inputs. The group averages are again illustrated as the mean over the subjects (solid line) and mean ± SE over the subjects (dashed line). The three kernel estimates via the Laguerre expansion method for Gaussian inputs were similar and thus not shown. The three kernels were not proportional to each other, thereby indicating that the model could not be further reduced.