I think Mike meant to say that p is only meaningful if you remember that it is conditionalized upon the null being true. Even if the null is never or almost never true, p as an abstract quantity can be meaningful, just like a sampling distribution is a meaningful thing even if it is never obtained. This is not to say that there are not even more meaningful things we could do with the measurements from which we typically derive these p values.
I disagree, however, with the assertion that replication (if that means repeating the research) is only useful if the null is rejected. With replication the base upon which a meta analysis can be conducted grows, allowing greater precision (less wide confidence intervals) when estimating effect sizes. Please keep in mind that a meta analysis can detect a non-zero effect size from a collection of studies each of which individually resulted in retention of the null. ----- Original Message ----- From: "Jean-Marc Perreault" <[EMAIL PROTECTED]> To: "Teaching in the Psychological Sciences" <[EMAIL PROTECTED]> Sent: Tuesday, November 12, 2002 5:56 PM Subject: RE: p is continuous, not dichotomous Mike, could you expand on how it is that a p-value is only meaningful if the Null is true? I understand the second part of your statement (Replication only useful is Null is rejected)... but would like more info on the first... cheers! Jean-Marc --- Mike Scoles <[EMAIL PROTECTED]> wrote: > A p-value is only meaningful if the null hypothesis is true. Replication is only meaningful if the null is false. > > > -----Original Message----- > > From: Martin J. Bourgeois [mailto:MartyB@;uwyo.edu] > > Sent: Tuesday, November 12, 2002 1:30 PM > > To: Teaching in the Psychological Sciences > > Subject: RE: p is continuous, not dichotomous > > > > > > Maybe I should quit before I get too far behind, > but what I'm trying to > > say (and apparently failing) is that an observed > difference between > > means is more likely to be replicated when the p > is .001 than when the p > > is .1. You can certainly calculate the probability > of replicating a > > result with a given p value, and results with > smaller p's are more > > likely to be replicated (yes, it has been > supported by data). I'll dig > > up a reference when a get a chance. > > > --- > You are currently subscribed to tips as: > [EMAIL PROTECTED] > To unsubscribe send a blank email to > [EMAIL PROTECTED] > > ===== Jean-Marc Perreault Arts & Sciences Yukon College Whitehorse, Yukon 867-668-8867 ______________________________________________________________________ Post your free ad now! http://personals.yahoo.ca --- You are currently subscribed to tips as: [EMAIL PROTECTED] To unsubscribe send a blank email to [EMAIL PROTECTED] --- You are currently subscribed to tips as: [EMAIL PROTECTED] To unsubscribe send a blank email to [EMAIL PROTECTED]
