data redbelly; input distance northhap; cards; 60 1 60 0 60 0 60 0 60 0 60 0 320 0 280 0 280 0 200 0 260 1 260 0 260 0 260 0 260 0 260 0 260 0 260 0 540 0 540 1 540 0 540 1 790 1 790 1 1020 1 1020 1 1020 1 1020 1 1796 1 1796 1 1796 1 1796 1 1270 1 1270 1 1270 1 ; proc logistic; model northhap=distance / link=normit; output out=pred; quit;