Calculating Median

I found an article on calculating the median in SQL (http://www.sqlservercentral.com/scripts/Miscellaneous/31775/), and after reading a Wikipedia article on it, I realized that it was incorrect for sample sets of even size. I left a comment with a version of the calc that accounts for this, with a copy of this code:

;WITH
TopHalf AS (
SELECT TOP 50 PERCENT DataValue
FROM DataSet
ORDER BY DataValue ASC
)
,BottomHalf AS (
SELECT TOP 50 PERCENT DataValue
FROM DataSet
ORDER BY DataValue DESC
)
,BottomOfTopHalf AS (
SELECT TOP 1 DataValue
FROM TopHalf
ORDER BY DataValue DESC
)
,TopOfBottomHalf AS (
SELECT TOP 1 DataValue
FROM BottomHalf
ORDER BY DataValue ASC
)
SELECT
Median = (BottomOfTopHalf.DataValue
+ TopOfBottomHalf.DataValue) / 2.0
FROM BottomOfTopHalf, TopOfBottomHalf