options ps=54 ls=76; data sol1; infile "../../data/solomon.dat"; input island $ 1-20 species 21-23 area 25-31 dist 33-39; logarea=log(area); dist=dist+0.01; run; proc print; run; proc nlin; parms b0=35 b1=5 b2=1 b3=1 b4=1; model species=(b0+b1*logarea)*exp((-dist**b2)/(b3*area**b4)); run; quit;