Figure 11
The use of smoothed absolute residuals to diagnose and quantify residual heteroscedasticity. 'Absolute residuals versus log2(Cy3)' scatter plot smoothed using supsmu and lowess and different values of the smoothing parameters bass and f, respectively. The figure illustrates the dependence of smoothing effect from magnitude of smoothing parameters. bass is control of the low frequency emphasis when using cross validation. The larger the value of bass (up to ten), the smoother the fit from automatic span selection [51, 52, 63]. f is fraction of the data used for smoothing at each log2(Cy3) point. The larger the f value, the smoother the fit [51, 52, 63].