At 12:59 PM 10/12/01 -0300, you wrote: >While consulting people from depts of statistics about this, a few of them >were arguing that these assumption testing are just a "legend" and that >there is no problem in not respecting them !
note: you should NOT respect any stat expert who says that there is no problem ... and not to worry about the so called "classic" assumptions all they are doing is making their consultation with you EASIER for them! every test you might want to do has 1 or more assumptions about either how samples were taken and/or parameters (and other things) about the population in some cases, violations of one or more of these make little difference in the "validity" of the tests (simulation studies can verify this) ... but, in other cases, violations of one or more can lead to serious consequences (ie, yielding a much larger type I error rate for example that you thought you were working with) ... there is no easy way to make some blanket statement as to what assumptions are important and which are not because ... this depends on a specific test (or family of similar tests) usually, for a particular test ... "good" texts will enumerate the assumptions that are made AND, will give you some mini capsule of the impact of violations TO those assumptions _________________________________________________________ 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/ =================================================================
