Chuck,
Take a read of Bob Witte¡¯s measurement equipment books, written when he was at HP. Joe Carr¡¯s tests and measurements book is another one rendering a cogent treatment of measurement errors without going very deep into the statistical deep-end. This work is based upon formal true-score theory: the central issue of which is whether the observed score¡¯s errors are correlated with the true score and/or the observed score.
73,
Frank
K4FMH
Frank K4FMH