BUG: why in scipy.integrate.trapz(y,x) using x,y from pd.read_csv does not give the right answer
Please, refer to this question in StackOverflow for more details:
http://stackoverflow.com/q/17252024/832621

The OP reads a csv using:

```
data_df = pd.read_csv("example.csv", sep="\t", index_col=0, names=["test"])
```

And when doing integration using the "Index" object at data_df.index it does not work, but works with data_df.index.values,,,,
Is it a bug?
Thank you!
Saullo
