Un esempio:
x1=rand(1555,1);
x2=rand(1555,1);
x3=rand(1555,1);
x4=rand(1555,1);
x5=rand(1555,1);
y=2*x1+3*x2+4*x3+5*x4+6*x5+2+x4.*x3;
X = [ones(size(x1)) x1 x2 x1.*x2 x1.*x3 x1.*x4 x1.*x5 x2.*x3 x2.*x4 x2.*x5 x3.*x4 x3.*x5 x4.*x5];
[b,bint,r] = regress(y,X);