install R言語 version 3.02 on Ubuntu

http://qiita.com/foloinfo/items/a7b38084add3bb70f6ca

# add source to apt.
sudo vim /etc/apt/sources.list
# add line below
deb http://cran.rstudio.com/bin/linux/ubuntu precise/

sudo apt-key adv --keyserver keyserver.ubuntu.com --recv-keys E084DAB9
sudo add-apt-repository ppa:marutter/rdev
sudo apt-get update
sudo apt-get upgrade
# install!
sudo apt-get install r-base