On Fri, 11 Oct 2013 07:29:35 -0700 (PDT), email@example.com wrote:
>On Thursday, October 10, 2013 7:08:03 PM UTC-4, Rich Ulrich wrote: > > <...some confirmations that small p-values do not demonstrate a > lack difference, and that the use of large p-values may be due to > historical lack of understanding, which may be improving...> > >> As a very general rule, p-levels are not good indicators of effect >> size. Or, conversely, for lack-of-effect size. N is the huge >> confounder, plus, it depends on how sensitive your test is for >> finding an "effect." > >Understood. I'm just focusing on acceptance/rejection of H0. >> >> When you want to show similarity, you want to show a narrow CI on >> some relevant difference, for some meaningful measure... not merely >> an absence of "demonstrated" difference. Crappy measures can give >> you apparent similarities. > >My understanding is that narrow CI can only show lack of evidence against H0, but can never show the evidence for H0.
As Herman says in a post that *seems* to reply to this (although he tacked on to your other comment from about the same time), it is an easy conventional comment that "The null hypothesis is never true."
A narrow CI on the size of a difference gives us evidence that the difference is not larger. Or, not large enough to matter.