Problem with pandas.Series.std()
Hi,

I ran the following commands on "pandas.Series" object named "S":

> > > S.std()
> > >  39192.660667875185
> > > S.values.std()
> > >  17570.025893232512
> > > numpy.std(S)
> > >  39192.500822771792
> > > numpy.std(S.values)
> > >  17570.025893232512

Correct standard deviation is 17570.02589
I should have got the same value in all 4 cases.

This seems to be a bug in pandas.Series
Pickle file for "S" object is here:
https://gist.github.com/yashoteja/4971970

Thank you,
Yashoteja
