most books talk about inferential statistics ... particularly those where you take a sample ... find some statistic ... estimate some error term ... then build a CI or test some null hypothesis ... error in these cases is always assumed to be based on taking AT LEAST a simple random sample ... or SRS as some books like to say ... but, we KNOW that most samples are drawn in a way that is WORSE than SRS ... thus, essentially every CI ... is too narrow ... or, every test statistic ... t or F or whatever ... has a p value that is too LOW ... what adjustment do we make for this basic problem? _________________________________________________________ dennis roberts, educational psychology, penn state university 208 cedar, AC 8148632401, mailto:[EMAIL PROTECTED] http://roberts.ed.psu.edu/users/droberts/drober~1.htm ================================================================= Instructions for joining and leaving this list and remarks about the problem of INAPPROPRIATE MESSAGES are available at http://jse.stat.ncsu.edu/ =================================================================
