For instance, x (sigma sub x-bar) is the standard deviation of sample means, or standard error of the mean. and can take subscripts to show what you are taking the mean or standard deviation of.
The letter sigma ( σίγμα), the 18th letter of the ancient Greek alphabet. Not sure about pure maths, but in applied mathematics & physics it is the recognised symbol for (a) the coefficient of friction (governing the motion of.( S) ( uppercase, nonfinal lowercase σ, final lowercase ς).( mathematics ) : Though there exists a distinct symbol ( ∑) for the purpose of the mathematical summation, the upper case sigma here is often used for convenience.Īncient Greek Alternative forms It is a measure of the amount of variation or dispersion in a set of values. ( mathematics ) A class (in the arithmetical hierarchy) of formulae whose outermost unbounded quantifiers are existential quantifiers sigma (): This symbol represents the standard deviation of a population.( topology ) suspension or reduced suspension.