Talk:Econometric Theory/Least Squares

'''I work with measuring machines, CMM's, which use least squares algorithm to calculate a circle size and center, based on 4 or more points. Three points define a circle but in the real world a 4th point will not be a perfect fit, especially if accuracy is in the micron level. Therefore, least square is used to "average" out all 4 points.'''

'''Least square is likewise used for 5 or more points on a cylinder. The result is a diameter, center location, and 2 offset angles from the coordinate system planes, for example a ZX plane angle and a YZ plane angle. 12 to 20 points make the calculation more accurate, but greatly increases the calculations.'''

'''I've never entered info in a wiki, so I just offer this as an invitation. Here is an incomplete article under "Least Squares, non-linear use." If I can steer someone with more details, contact me "AT" kcp.com - name "wboyer".'''