As a programmer and statistician I should warn newcomers about the assumptions of tests (parametric tests like test t). Test t for example need same variance and normality or you'll take wrong decisions. These formulas and p-values shouldn't be used as substitutes for graphics (you should check them first and test later).

Just take care, there's a lot of problems from using statistics in wrong way. special care with small sample size and even large ones [http://scienceblogs.com/mixingmemory/2006/10/31/jeffreylindl...]