Does MLab.std() dislike Numeric.UnsignedInt8?

[Kyler Laird]

Python 2.3.3 (#2, Jan 4 2004, 12:24:16)
[GCC 3.3.3 20031229 (prerelease) (Debian)] on linux2
Type "help", "copyright", "credits" or "license" for more information.
>>> import Numeric
>>> import MLab
>>> import Scientific.Statistics
>>> MLab.std(Numeric.array([255,255], Numeric.Int0))
0.0
>>> MLab.std(Numeric.array([255,255], Numeric.UnsignedInt8))
181.01933598375618
>>> Scientific.Statistics.standardDeviation(Numeric.array([255,255], Numeric.UnsignedInt8))
0.0

It seems to me that the return values should all be the same. Am I missing
something simple?

--kyler