主成分分析：是一种数据降维技巧。

princomp

install.packages("psych")

library(psych)

USJudgeRatings

class(USJudgeRatings)

fa.parallel(USJudgeRatings,fa="pc",n.iter=100)  碎石图：1

pc<-principal(USJudgeRatings,nfactors=3,rotate="none",scores=FALSE)

 

fa.parallel(Harman23.cor$cov,n.obs=302,fa="pc",n.iter=100,show.legend=FALSE)碎石图：2

 

 

pc<-principal(Harman23.cor$cov,nfactors=2,rotate="none")

fa.parallel(x,fa="pc",n.iter=100)

pc<-principal(x,nfactors=3,rotate="none",scores=FALSE)