Hi, Could you give me your opinions on this idea, please ? Predicting Y from X is similar* to finding the Expectation{Y|X}. The joint probability Pr(X,Y) 'contains' this expectation. If this joint probability follows a 'simple' law, it is easier to estimate it directly than using regression techniques. Thanks, Claus *when using least sqares error ---------------------------------------------------------------- This message was sent using IMP, the Internet Messaging Program.