Hi, If all the signs are switched the PC's are still the same. The principal vectors are along the same axis, only in a different direction. So there is no problem :).
hope this helps, Paul On 09/09/2011 09:01 AM, René Mayer wrote: > Dear All, > > when I'm running a PCA with > > prcomp(USArrests, scale = TRUE) > > I get the right principal components, but with the wrong sign infront > > Rotation: > PC1 PC2 PC3 PC4 > Murder 0.5358995 -0.4181809 0.3412327 0.64922780 > Assault 0.5831836 -0.1879856 0.2681484 -0.74340748 > UrbanPop 0.2781909 0.8728062 0.3780158 0.13387773 > Rape 0.5434321 0.1673186 -0.8177779 0.08902432 > > instead of > > PC1 PC2 PC3 PC4 > Murder -0.5358995 0.4181809 -0.3412327 0.64922780 > Assault -0.5831836 0.1879856 -0.2681484 -0.74340748 > UrbanPop -0.2781909 -0.8728062 -0.3780158 0.13387773 > Rape -0.5434321 -0.1673186 0.8177779 0.08902432 > > what is happening here? > any ideas? > > thanks, > René > > ______________________________________________ > [email protected] mailing list > https://stat.ethz.ch/mailman/listinfo/r-help > PLEASE do read the posting guide > http://www.R-project.org/posting-guide.html > and provide commented, minimal, self-contained, reproducible code. -- Paul Hiemstra, Ph.D. Global Climate Division Royal Netherlands Meteorological Institute (KNMI) Wilhelminalaan 10 | 3732 GK | De Bilt | Kamer B 3.39 P.O. Box 201 | 3730 AE | De Bilt tel: +31 30 2206 494 http://intamap.geo.uu.nl/~paul http://nl.linkedin.com/pub/paul-hiemstra/20/30b/770 ______________________________________________ [email protected] mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.
