Re: Sample Size

From: LSheiner <lewis@c255.ucsf.edu> Subject: Re: Sample Size Date: Mon, 12 Jun 2000 09:34:05 -0700 A difficult question. Unfortunately, it's entirely up to you; there is no general rule. The basic theory (decision theory) assigns costs and probabilities under various courses of action to all relevant states of nature and then advises taking the course of action with least expected cost. The probabilities are where the "acceptable amount of error" come in. In this spirit, you might ask yourself how big a mistake you could tolerate without substantial loss, or some similar question to determine your tolerable range of uncertainty. Generally, for parameters affecting dosage magnitude, e.g. clearance, it is believed (without much empirical evidence one way or the other) that +/- 25 50% is sufficient ... LBS. -- _/ _/ _/_/ _/_/_/ _/_/_/ Lewis B Sheiner, MD (lewis@c255.ucsf.edu) _/ _/ _/ _/_ _/_/ Professor: Lab. Med., Bioph. Sci., Med. _/ _/ _/ _/ _/ Box 0626, UCSF, SF, CA, 94143-0626 _/_/ _/_/ _/_/_/ _/ 415-476-1965 (v), 415-476-2796 (fax)