object used in example but not created there
In [here](http://pandas-docs.github.io/pandas-docs-travis/groupby.html#groupby-with-multiindex) object `s` is used in the example but not created on this page (at least in this form).

Above it is created as series

``` python

In [8]: s = pd.Series([1, 2, 3, 10, 20, 30], lst)
```

once under  [here](http://pandas-docs.github.io/pandas-docs-travis/groupby.html#groupby-with-multiindex)

``` python
In [27]: s
Out[27]: 
first  second
bar    one      -0.575247
       two       0.254161
baz    one      -1.143704
       two       0.215897
foo    one       1.193555
       two      -0.077118
qux    one      -0.408530
       two      -0.862495
dtype: float64
```

is completely different thing.

I find referring to objects created on other manual pages very confusing. 
