function [A,b] = LSRegression(X,Y)

[D,N] = size(X);

EX = sum(X,2)/N;

CovX = X*X'/N - EX*EX';

EY = sum(Y,2)/N;

CovXY = Y*X'/N - EY*EX';

A = CovXY * inv(CovX);

b = EY - A*EX;

figure(1);clf;
minX = min(X(1,:));
maxX = max(X(1,:));
x=minX:0.01:maxX;
plot(X(1,:),Y(1,:),'o');hold on;
plot(x,A(1,1)*x+b(1),'r-');
drawnow;