No, it means find a result in the same direction. Chris Green ===========
Michael Smith wrote: > > I'm not sure. But if the "probabilty of replication" means the same as > finding a statistically significant result by repeating an experiment > exactly as before, then the probability of such a replication is > exactly 50% (assuming an alpha of exactly 0.05) > > --Mike > > */"Wuensch, Karl L" <[EMAIL PROTECTED]>/* wrote: > > I don't understand why the "probability of replication" is of > any importance. You can "replicate" any effect given sufficient > power/N. N is not held constant across different calculations of > p-rep, > is it? What of value does p-rep give one that is not already in hand > when a confidence interval for the effect size is provided? > > ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ > Karl L. Wuensch, Professor and ECU Scholar/Teacher, Dept. of > Psychology > East Carolina University, Greenville NC 27858-4353, USA, Earth > Voice: 252-328-9420 Fax: 252-328-6283 > [EMAIL PROTECTED] > http://core.ecu.edu/psyc/wuenschk/klw.htm > > -----Original Message----- > From: Marc Carter [mailto:[EMAIL PROTECTED] > Sent: Friday, November 16, 2007 12:04 PM > To: Teaching in the Psychological Sciences (TIPS) > Subject: RE: [tips] p-rep, mathematical error, pure and simple < Pro > Bono Statistics > > > Forgive this horribly un-sourced response, but there is (and has been, > nearly from the get-go) a debate about whether p(rep)'s > assumptions are > correct in its original formulation. The problem has to do with (iirc) > the estimation of effect sizes, which are required for computing > p(rep). > (Those are the lower-case deltas, I believe, in Gat's blog post.) Gat > adds in a later post > > onal-science/> that the error has been pointed out already. > > I'm not statistician, but I suspect that this is going to work itself > out. The idea is fundamentally sound, and if it's possible to make > reasonable assumptions about effect sizes (or the distributions of > that > variable), then one *should* be able to compute the probability of a > replication. I'm waiting for things to calm down a bit and for people > far smarter than me to figure it out. Again, I'm not a statistician, > but I don't see immediately why that difficulty kills the idea. > > I'm talking to my stats classes about it so that they'll be aware that > it's probably something they're going to see in the future (and if > they > read APS journals, they'll see now), but I'm not teaching it, per se. > It doesn't seem to me that anyone has launched a devastating > critique of > the idea of it, but rather have found problems with the computation of > it. > > m > > ------ > "There is no power for change greater than a community discovering > what > it cares about." > -- > Margaret Wheatley > > -----Original Message----- > From: Christopher D. Green [mailto:[EMAIL PROTECTED] > Sent: Friday, November 16, 2007 9:28 AM > To: Teaching in the Psychological Sciences (TIPS) > Cc: Robert A. Cribbie; David Flora; Michael Friendly; Doba Goodman > Subject: [tips] p-rep, mathematical error, pure and simple < Pro Bono > Statistics > > > There has been a lot of excitement around a statistic being used > in APS > journals of late called p-rep. It was developed by Peter Killeen, > published in a 2005 issue of Psychological Science. The primary > advantage claimed for it is that it gives the average probability of > replicating a given effect in future studies, rather than giving the > probability, under the null hypothesis, of finding data at least as > improbable as that actually found (which is roughly what good ol' > p-values give). > > But now I have found a blog posting by a California statistician named > Yoram Gat that claims that Killeen's derivation is based on a > "mathematical error, pure and simple." You can find the posting at: > http://probonostats.wordpress.com/2007/09/15/p-rep-mathematical-error-pu > re-and-simple/ > > He details what the error is, but I am not statistically sophisticated > enough to know whether or not he is correct. Has anyone else come > across > this? Is Gat right? And, if he is, is the error as devastating to > p-rep > as he claims? > > Regards, > Chris Green > York U. > Toronto, Canada > > > --- > To make changes to your subscription contact: > > Bill Southerly ([EMAIL PROTECTED]) > > --- > > --- > > > ------------------------------------------------------------------------ > Be a better pen pal. Text or chat with friends inside Yahoo! Mail. See > how. <http://us.rd.yahoo.com/evt=51732/*http://overview.mail.yahoo.com/> > --- > To make changes to your subscription contact: > > Bill Southerly ([EMAIL PROTECTED]) > ---
