Psychometric & Aptitude Tests?

I have recently been ped over for promotion and after pestering the HR Dept to provide some form of explanation why they chose someone just out of university (6 months exp) rather than me (7 years exp) they told me that my psychometric & aptitude tests indicated I was administration not management material. So I need to know (1) how can these tests really be so certain (2) does any one know of any book or website to enable me to get a different result to these tests if I take them in the future?