Install new version of R-base in Ubuntu

From: http://www.sysads.co.uk/2014/06/install-r-base-3-1-0-ubuntu-14-04/

Step 1: Uninstall Previous R-base installation

sudo apt-get remove r-base-core

Step 2: Update Sources.List File

- Edit the sources.list file

sudo gedit /etc/apt/sources.list

- Add following entry

deb http://cran.rstudio.com/bin/linux/ubuntu precise/

Step 3: Add the Public Keys

gpg --keyserver keyserver.ubuntu.com --recv-key E084DAB9

gpg -a --export E084DAB9 | sudo apt-key add -

Step 4: Install R-base

sudo apt-get update

sudo apt-get upgrade

sudo apt-get install r-base

Step 4: Launch R-base

R