I have values for three different variables Z ,X,Y : how can i get the least square regression equation of Z on X and Y

I have values for three different variables Z ,X,Y : how can i get the least square regression equation of Z on X and Y

Answer 1

[the cyclist]

You could use either the regress() function or the LinearModel.fit() function.

doc regress

or

doc LinearModel.fit

for details.

In each case, you'll need to combine your X and Y values into one array (predictor variables) and use Z for the response variable.

[mohamed]

sorry, i want to know how to combine my X and Y values into one array

[the cyclist]

If X and Y are column vectors, then you can combine them as so:

[X Y]

Answer 2

[Image Analyst]

I use John D'Errico's polyfitn(): http://www.mathworks.com/matlabcentral/fileexchange/34765-polyfitn