Confidence limits for the independent variable in bivariate       (STB-9: sg10)
linear regression
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          ^confx^ depvar indepvar yobsvar #

Description
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^confx^ computes the 95 percent or other confidence limits for the
X variable "Xest" estimated from a set of Y observations "yobsvar"
on samples with unknown amounts of X present.  The program first
performs linear regression of Ystd (depvar) on Xstd (indepvar)
where Xstd is a set of standards treated by some analytical method
and Ystd is the responses observed.  The value of # should be typed
90, 95, 99 or whatever is desired.  

The output gives the X estimates of the unknowns "Xest" and their
upper and lower confidence values "Ulim" and "Llim".

Please type ^d^escribe or ^l^ist to see results.

The equations used are found in Snedecor, G.W. and Cochran, W.G.
1989.  Statistical Methods, 8th edition.  Iowa State University
Press: Ames, IA, pp 170-172.

Author:   Paul J. Geiger, USC School of Medicine