Factor Analysis in MASS4
On Thu, 29 Aug 2002, Ko-Kang Kevin Wang wrote:
Hi,
I had a look at the MASS4 scripts in the MASS package, in Ch 11.3 Factor
Analysis, there is a section of codes like:
data(ability.cov)
ability.FA <- factanal(covmat = ability.cov, factors = 1)
ability.FA
(ability.FA <- update(ability.FA, factors = 2))
#summary(ability.FA)
round(loadings(ability.FA) %*% t(loadings(ability.FA)) +
diag(ability.FA$uniq), 3)
Unfortunately I still haven't received the book I ordered, so I can't look
this up.
Two questions:
1) What does the update() do? I mean, what happens if I replace it with
factanal(covmat = ability.cov, factors = 2)
That's what it does. update always recalls the original call with the changes as given.
2) What does the last command, the formulae in round() mean? I tried it and it produced a matrix that looks kind of like correlation matrix of some sort...
It is the fitted correlations.
Brian D. Ripley, ripley at stats.ox.ac.uk Professor of Applied Statistics, http://www.stats.ox.ac.uk/~ripley/ University of Oxford, Tel: +44 1865 272861 (self) 1 South Parks Road, +44 1865 272860 (secr) Oxford OX1 3TG, UK Fax: +44 1865 272595 -.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.- r-help mailing list -- Read http://www.ci.tuwien.ac.at/~hornik/R/R-FAQ.html Send "info", "help", or "[un]subscribe" (in the "body", not the subject !) To: r-help-request at stat.math.ethz.ch _._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._