STDEV and STDEVP

Accepted answer is wrong,
reference:http://office.microsoft.com/en-us/excel/HP052092811033.aspx

STDEV divides by N-1 and STDEVP divides by N

in reference to: http://www.experts-exchange.com/Microsoft/Development/MS-SQL-Server/Q_21998251.html (view on Google Sidewiki)