Type III errors

[Karl L. Wuensch]

Recently there was a discussion here involving the phrase "Type III errors." I noted that others have used that phrase to mean inferring the incorrect direction of effect after rejecting a nondirectional hypothesis, but I was unable to give references. This week I stumbled across references to such use of the term. Interested parties may consult the article by Leventhal and Huynh (Psychological Methods, 1996, 1, 278-292). They recommend that the probability of making a Type III error be subtracted from the probability of correctly rejecting the nondirectional null when computing power (since it is common practice to infer a direction of effect following rejection of a nondirectional null. I have posted a summary of the article at: http://core.ecu.edu/psyc/wuenschk/StatHelp/Type_III.htm +++++++++++++++++++++++++++++++++++++++++ Karl L. Wuensch, Department of Psychology, East Carolina University, Greenville NC 27858-4353 Voice: 252-328-4102 Fax: 252-328-6283 [EMAIL PROTECTED] http://core.ecu.edu/psyc/wuenschk/klw.htm