Fig.4: Confidence ellipses for DNA fragment 2 (118 bp) derived from modeling the concave Ferguson plots shown in Fig.1, treating fragment 2 as an unknown particle. The 95 % confidence envelopes are shown for the fitted parameters of free mobility and effective particle radius. Solid line: no common free mobility intercept is assumed. Dashed line: a single common value of free mobility was fitted. The ellipses were generated by program ElphoFit using rationales of (36,18).