$ sudo apt-get update
$ sudo apt-get install python-scikits-learn 

python-scikits-learn is installed in your system.

Make ensure the python-scikits-learn package were installed using the commands given below,

$ sudo dpkg-query -l | grep python-scikits-learn *

You will get with python-scikits-learn package name, version, architecture and description in a table

python-scikits-learn package basic information: