Added population average deviation.
Added population average deviation.

v0dro/statsample,v0dro/statsample,IsmailM/statsample,jaredpohl/statsample,IsmailM/statsample,mikecmpbll/statsample,SciRuby/statsample,SciRuby/statsample,mikecmpbll/statsample,jaredpohl/statsample,clbustos/statsample,IsmailM/statsample,michaelphines/statsample,michaelphines/statsample,v0dro/statsample,michaelphines/statsample,mikecmpbll/statsample,clbustos/statsample