Date: Aug 17, 2012 9:39 PM
Author: Richard Ulrich
Subject: Re: comparison between two value in a sample, please help...
On Fri, 17 Aug 2012 01:49:39 -0400, Rich Ulrich

<rich.ulrich@comcast.net> wrote:

[snip, a bunch]

>

>I *think* what follows is a safe, conservative procedure --

>The minimum, proper fitted equation will show no less error

>than the measurement error. For that, the pooled SD is

Keep in mind that the MS-residual is an estimate of the variance

(which is the square of the standard deviation) of the residual.

When I was learning to use regression, it helped me when

I realized that fact. Then I started making a point of noticing that

variance, and taking the square root ... just to make sure that

I was still analyzing the same set that I thought I was, and that

nothing was going strange.

>about 42, or the "Mean-square-residual" is the square of

>42, with 10 d.f. Take the Mean square for Regression from

>the 5-point regression and divide it by *this* residual,

>instead of the computed residual, to get the safe F-test.

Oops! slligh correction -- For the 5 point regression, each

point is the average of three measures. The SD of the *3*

taken separately is 42; the SD of the average is, naturally,

the raw SD divided by the square root of N, or sqrt(3).

Or - the MS is not 42-squared, but is 42-squared, divided

by 3.

>

>The ratio of the two so-called Residual terms can be used as

>a test of whether the regression is "over fitted".

>

Still useful, but you do use the corrected value.

--

Rich Ulrich