Shouldn't it be, "The Earth is round (B<.05)"? After all, the null hypothesis would be that the Earth was round, and rejecting it would give you, "The Earth is not round (P<.05)"
According to Cohen, you can only accept a null hypothesis to be true if the power was high enough to detect the smallest relevant effect size. Thus, if the Earth did not differ significantly from being round, and you had a high enough power to detect a relevant degree of "roundness", then you could declare the Earth was round (Power = 0.95, or B = 0.05; or whatever your acceptable cutoff for power). The p, of course, would be bigger than 0.05, or whatever value of alpha you are using. Although I am not worthy enough of statistics to comment on this, some statisticians say you should never use a P-value. But that is for Bayesians to comment upon... Cheers, Shane Opinions expressed are those of the author and do not represent those of his employer. > -----Original Message----- > From: Ecological Society of America: grants, jobs, news > [mailto:[EMAIL PROTECTED] On Behalf Of Anon. > Sent: Monday, February 27, 2006 11:20 AM > To: [email protected] > Subject: Re: hypothesis testing vs descriptive statistics > > > Malcolm McCallum wrote: > > I vaguely recall an exchange on here regarding the role of > hypothesis > > = testing and the statistical validity of this approach. Any > > citations or = comments would be greatly apprecieated! > > There's enough here to keep you going: > <http://www.warnercnr.colostate.edu/~anderson/thompson1.html> > > This is probably one of the more important papers: it sparked > off a big > discussion amongst pshycologists: > Cohen, J. 1994. The earth is round (p<.05). American Psychologist > 49:997-1003. > > My only comment is to observe that nobody should be allowed to use a > p-values unless they can demonstrate that they fully > understand what it > means. > > Bob > > -- > Bob O'Hara > > Dept. of Mathematics and Statistics > P.O. Box 68 (Gustaf H"llstr"min katu 2b) > FIN-00014 University of Helsinki > Finland > > Telephone: +358-9-191 51479 > Mobile: +358 50 599 0540 > Fax: +358-9-191 51400 > WWW: http://www.RNI.Helsinki.FI/~boh/ > Journal of Negative Results - EEB: http://www.jnr-eeb.org >
