Figure 2.

Residuals for the link density property for the fourth-order polynomial regression (A) and for the discontinuous piecewise linear regression (B). Heteroscedasticity can be demonstrated by fitting a linear regression to the absolute values of the residuals (see Table 1). The residuals display heteroscedasticity for all webs in A and for the small webs in B. A line separates the large webs (n = 36) from the small webs (n = 24) in B. Only the residuals of large webs with the piecewise model exhibit homogeneous variances.