% Emacs mode header: -*-Octave-*- source. %
%%  #! /usr/bin/octave -qf 

fYD4 = [125, 51; 250, 30; 500, 16; 1000, 11; 2000, 24]
 p = polyfit(fYD4(:,1),fYD4(:,2),2);
 x1 = linspace(100,2000);
 y1 = polyval(p,x1);
hold on 
plot(x1,y1)
semilogx(fYD4(:,1),fYD4(:,2));
%