In a message dated 7/3/2001 2:35:34 PM US Eastern Standard Time, [log in to unmask] writes: << Many people would say something like 25. It's entirely arbitrary and no theory can tell you how many are enough. 25 comes from the reasoning that, under most circumstances, 25 samples will make the sample s.dev. a somewhat reliable estimate of the population s.dev. >> I agree with your reasoning. We always use 30, for very much the same logic. Jon Moore --------------------------------------------------------------------------------- Technet Mail List provided as a free service by IPC using LISTSERV 1.8d To unsubscribe, send a message to [log in to unmask] with following text in the BODY (NOT the subject field): SIGNOFF Technet To temporarily halt delivery of Technet send the following message: SET Technet NOMAIL Search previous postings at: www.ipc.org > On-Line Resources & Databases > E-mail Archives Please visit IPC web site (http://www.ipc.org/html/forum.htm) for additional information, or contact Keach Sasamori at [log in to unmask] or 847-509-9700 ext.5315 ---------------------------------------------------------------------------------