fig2_5

 Local Regression and Likelihood, Figure 2.5.

 Using different smoothing parameters.

0001 % Local Regression and Likelihood, Figure 2.5.
0002 %
0003 % Using different smoothing parameters.
0004 
0005 load ethanol;
0006 
0007 alp = [0.2 0.4 0.6 0.8];
0008 f=['a','b','c','d'];
0009 for (i=1:4)
0010   figure('Name', sprintf( 'figure2_5%c: Smoothing parameters', f(i) ) );
0011   fit = locfit(E,NOx,'alpha',alp(i));
0012   res = residuals(fit);
0013   fit2 = locfit(E,res,'alpha',0.2);
0014   lfplot(fit2);
0015   title(strcat('a = ',num2str(alp(i))));
0016   ylabel('Residual');
0017   hold on;
0018   plot([min(E) max(E)], [0 0], ':');
0019   hold off;
0020 end;