Anatomy of a Microbiological Collaborative Test. H. Raymond Helbert, Miller Brewing Company, Milwaukee WI 53201. J. Am. Soc. Brew. Chem. 35:0137, 1977.

This report pertains to the statistical design and analysis of a microbiological collaborative test, viz., the collaborative testing by the ASBC Subcommittee for Microbiological Controls during 1975-1976 (1). A complete factorial design was used in conjunction with an analysis of variance. The rationale for using these methods, with some of their underlying assumptions, is discussed. One way of dealing with the non-Gaussian distribution of most microbiological data is detailed. Interpretation of both the main effects and the interactions of experimental factors is also treated.

Keywords: Analysis of variance, Components of variance, Factorial design, non-Gaussian distribution.