I am using iPython on OSX (on system, not inside a virtualenv) and importing pandas into a notebook. My system python is Python 2. 

The version of pandas visible in the notebook is 0.16.2:

```
import pandas as pd
print pd.__version__

```

I want to use pandas 0.18. So I have quit the notebook and run:

```
pip install --upgrade ipython
pip install --upgrade pandas

```

This appeared to install ipython 4.1.2 and pandas 0.18.0, but if I run:

```
ipython --version

```

I see v4.0. And running my notebook still shows pandas 0.16.2.

How do I upgrade my packages so that I can use pandas 0.18 inside my notebook?