[SciPy-user] Possible bug in stats.describe

Christopher Mutel cmutel at gmail.com
Thu Jun 8 22:13:40 CDT 2006


I am using the Ubuntu pre-packaged version of SciPy (0.3.2-3ubuntu2).
In my version, as best as I can tell, the stats.describe function is
incorrect. It gives the variance of a sample, not the standard
deviation. Could someone confirm that I am reading this right?

>From my stats.py:

def describe(a,axis=-1):
     """Returns several descriptive statistics of the passed array.  Axis
     can equal None (ravel array first), or an integer (the axis over
     which to operate)

     Returns: n, (min,max), mean, standard deviation, skew, kurtosis
     a, axis = _chk_asarray(a, axis)
     n = a.shape[axis]
     mm = (minimum.reduce(a),maximum.reduce(a))
     m = mean(a,axis)
     v = var(a,axis)
     sk = skew(a,axis)
     kurt = kurtosis(a,axis)
     return n, mm, m, v, sk, kurt

This is the first time I have ever suspected a bug, so maybe I am
doing this all wrong. Or has this been noticed already and fixed?

-Chris Mutel

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