This function computes the process standard deviation and is used internally by the function precision.grubbs.ncb.od.
A matrix or numeric data.frame consisting of an n (no. of items) by N (no. of methods) matrix of measuremnts.
The process standard deviation is the standard deviation of the true values uncontaminated by measurement error. See Jaech, p. 185.
A scalar containing the method of moments estimate of the process standard deviation.
Richard A. Bilonick
Jaech, J. L. (1985) Statistical Analysis of Measurement Errors. New York: Wiley.