RE: [R] statistical significance test for cluster agreement

2004-03-24 Thread Alexander Sirotkin \[at Yahoo\]
Like you said, such kind of test will not give me anything that Rand index does not, except for p-value. The null hypothesis, in my case, is that clustering results does not match a different clustering, that someone alse did on the same data. And I do believe that this hypothesis is valid.

RE: [R] statistical significance test for cluster agreement

2004-03-24 Thread Liaw, Andy
[Apology to the list for the off-topic rant...] As it turned out, I also have a problem with LOF/GOL/etc. tests: I'd bet most of the time when such a test is carried out, it is _not_ the only test being done, but the p-values in the downstream analysis are almost never adjusted for this. How

RE: [R] statistical significance test for cluster agreement

2004-03-24 Thread Christian Hennig
Dear Alexander, On Wed, 24 Mar 2004, Alexander Sirotkin [at Yahoo] wrote: Like you said, such kind of test will not give me anything that Rand index does not, except for p-value. The null hypothesis, in my case, is that clustering results does not match a different clustering, that

RE: [R] statistical significance test for cluster agreement

2004-03-24 Thread Alexander Sirotkin \[at Yahoo\]
Christian, I think I understand your point, but I do not completely agree with you. I also did not describe my problem clear enough. If you see two clusterings on the same data, they are identical, if they are 100% identical, and if not, then not. What you are actually saying is that all

RE: [R] statistical significance test for cluster agreement

2004-03-24 Thread Liaw, Andy
From: Alexander Sirotkin [at Yahoo] [mailto:[EMAIL PROTECTED] Christian, I think I understand your point, but I do not completely agree with you. I also did not describe my problem clear enough. If you see two clusterings on the same data, they are identical, if they are 100%

Re: [R] statistical significance test for cluster agreement

2004-03-23 Thread Duncan Murdoch
On Tue, 23 Mar 2004 15:27:14 -0800 (PST), you wrote: I was wondering, whether there is a way to have statistical significance test for cluster agreement. I know that I can use classAgreement() function to get Rand index, which will give me some indication whether the clusters agree or not, but

RE: [R] statistical significance test for cluster agreement

2004-03-23 Thread Liaw, Andy
But what would such a test do that the rand index does not? Would you interpret the p-value from such a test, if exists, to have the meaning that a real test of hypothesis has? AFAIK you basically need to have the hypotheses pinned down even before you see any data, for the inference to be