Some tests have been known to contain inherent racial or gender bias. For example, below is a link to a simple test. How many rounds are fired with each hand in this video?
http://www.youtube.com/watch?v=8MLSRfT3NDc
(stolen from GlockTalk.com)
http://www.youtube.com/watch?v=8MLSRfT3NDc
(stolen from GlockTalk.com)