When applying reduction operations to Panel objects with axis > 0, the resulting DataFrame is transposed.  This seems to be intended behavior, but it leads to this function returning a transposed result, which may be unexpected since there is no outward indication that an aggregate method is being used here.  So without actually reading the source code, someone can't know that the Panel result will be transposed for certain axes.

So I chose to transpose it back, to make it consistent with all other data types.  However, I am not certain that is the correct approach.  Perhaps keeping it consistent with Pandas apply is better.