More specifically, if formula_1 are "n" identical and independently distributed random variables with mean formula_2 and standard deviation formula_3, then the distribution of their sample mean, formula_4, as "n" gets large, is approximately normal with mean formula_2 and standard deviation formula_6. Furthermore, the distribution of their sum, formula_7, as "n" gets large, is also approximately normal, with mean formula_8 and standard deviation formula_9. 