load linefit.dat;
x = linefit(:,1);
y = linefit(:,2);
figure(1), plot(x,y,'o');
% Use polyfit function to generate coefficiants for linear fit:
pcoeff = polyfit(x,y,1);
% Use this in polyval function to generate line:
xp = linspace(0,7,100);
yp = polyval(pcoeff,xp);
figure(2), plot(x,y,'o',xp,yp,'m');
% Use polyfit function to generate coefficiants for QUADRATIC fit:
pcoeff2 = polyfit(x,y,2);
yp2 = polyval(pcoeff2,xp);
figure(3), plot(x,y,'o',xp,yp2,'m')
% Calculate the E2 error at specific data points:
yp3 = polyval(pcoeff2,x);
n = length(x);
E2 = sqrt( sum( abs(yp3-y).^2)/n);