R: Psychometrics

From MathWiki

There is a package called "psy"

> install.packages("psy")
> library( psy )
> help.start()   # and consult the 'packages' link
> ?cronbach
> library( mvtnorm )
> vmat <- 0.2 * diag(10) + .8
> vmat
> datamat <- rmvnorm( 100, sigma = vmat)
> cronbach( datamat )
> datamat 

> by( datamat, datamat$Sex, function(dd) cronbach( dd[,c(3,4,2)]))