Bioassay of a cigarette smoke fraction, II. Experimental design and potency estimations

A series of experimental designs aimed at collecting and analyzing ciliostasis data in the most efficient and statistically valid manner was examined. The design that proved best for assessing water-soluble tobacco smoke samples in the hamster tracheal ring system utilized two dose levels of the University of Kentucky 1R1 reference cigarette (which functions as a reference as well as a continuing check on the dose-response relation in each experiment) plus several test tobacco smoke samples, each at a single dose level. A pair of animals formed the basis of a randomized block design, with one of the technician X sample preparation degrees of freedom confounded with animal differences within a pair. Assessment of the test samples can thus be expressed in terms of potency relative to the 1R1 reference. Control chart procedures were an essential facet of the system. Details of experiments and methods of data analysis are presented as examples of some of the steps required ot establish valid bioassay systems.