Kevin M. Lausten wrote: > I am having difficulty understanding how regressions perform. I have > 2 vectors (x = [4, 4, 0], y = [3, 6, 3]) and want to map y to x. When > this is done using a regression formula, I get a = 3 and b = .375. > Now, when I map x to y I get a = 0 and b = 2/3. Why is the second > result not the reflfective inverse of the first?(about the line y = > x)?
Regression minimizes the sum of squares of the vertical deviations of the data point to the line. If you flip the axes, you are minimizing a different quantity, and hence the line is in a different place. You can't simply flip the axes and expect the line to flip with it. If you want to flip the axes and see the line flip as you described, you need a different method; a method called orthogonal regression does exactly what you described. But orthogonal regression usually is not appropriate to use in real world problems where regression is appropriate, and vice versa. -- Paige Miller Eastman Kodak Company [EMAIL PROTECTED] http://www.kodak.com "It's nothing until I call it!" -- Bill Klem, NL Umpire "When you get the choice to sit it out or dance, I hope you dance" -- Lee Ann Womack . . ================================================================= Instructions for joining and leaving this list, remarks about the problem of INAPPROPRIATE MESSAGES, and archives are available at: . http://jse.stat.ncsu.edu/ . =================================================================
