None: basic R comes with a package `stats' that does both (very well!).
It is loaded by default.
You do need to read `An Introduction to R', as the posting guide asks.
On Mon, 2 May 2005, alessandro carletti wrote:
> what package could I install to best perform a
> Multiple Linear Regression (and what for PCA)?
> PLEASE do read the posting guide!
http://www.R-project.org/posting-guide.html
--
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 272866 (PA)
Oxford OX1 3TG, UK Fax: +44 1865 272595