[EMAIL PROTECTED] (Robert J. MacG. Dawson) wrote in news:[EMAIL PROTECTED]:
> Isn't there a QC teaching expreriment (by Deming?) designed to > make > this point - that the strategy of chasing your last error is not as > good as a consistent one? Yeah, it's known as the funnel experiment; it involves dropping marbles through a funnel onto a piece of paper and recording where they hit. The objective is to minimize the spread of the hit points. It shows that various strategies for moving the funnel based on how far off the "target" the last marble hit all result in greater spread than keeping the funnel stationary. The point is that you simply can't cancel out *random* variation with negative feedback; if a process is varying excessively and much of the variation is random noise, the only way to stabilize it is to locate and remove the noise sources, not to apply a classical control system to the process. . . ================================================================= Instructions for joining and leaving this list, remarks about the problem of INAPPROPRIATE MESSAGES, and archives are available at: . http://jse.stat.ncsu.edu/ . =================================================================
