Help: partial.cor significance test
Dear Simon, The population partial correlation rho[12|3...p] is 0 when the regression coefficient beta[2] for x[2] from the regression of x[1] on x[2] ... X[p] is 0. Thus, the usual t-test for a regression coefficient also tests that the partial correlation is 0. Now, the sample partial correlation r[12|3...p] = t/sqrt(t^2 + dfe)) where dfe = n - p is the degrees of freedom for error and t is the t-statistic for testing that beta[2] is 0, and thus t = sqrt(dfe*r^2[12|3...p]/(1 - r^2[12|3...p])), so it is easy to compute the (unsigned) t-statistics from the partial correlations. Why one would want to do this, however, is another matter. What would one do with a matrix of 2-sided p-values? Regards, John -------------------------------- John Fox Department of Sociology McMaster University Hamilton, Ontario Canada L8S 4M4 905-525-9140x23604 http://socserv.mcmaster.ca/jfox --------------------------------
-----Original Message----- From: r-help-bounces at stat.math.ethz.ch [mailto:r-help-bounces at stat.math.ethz.ch] On Behalf Of sp219 Sent: Wednesday, October 26, 2005 5:09 AM To: r-help at stat.math.ethz.ch Subject: [R] Help: partial.cor significance test Hi, I have been using the partial.cor function in Rcmdr but I was wondering if there is any easy way to get statistical significance tests (two tailed) along with the partial correlation coefficients? Simon Pickett Simon Pickett Centre for Ecology and Conservation Biology University of Exeter in Cornwall Tremough Campus Penryn Cornwall TR10 9EZ UK Tel: 01326371852
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