the law of averages

: a binding custom or practice of a community : a rule of conduct or action prescribed (see prescribe 1a) or formally recognized as binding or enforced by a controlling authority

: the whole body of such customs, practices, or rules

: common law

: litigate

: to sue or prosecute at law

: a single value (such as a mean, mode, or median) that summarizes or represents the general significance of a set of unequal values

: mean

: an estimation of or approximation to an arithmetic mean

: equaling an arithmetic mean

: being about midway between extremes

: not out of the ordinary : common

: to be or come to an average

: to have a medial value of

: to buy on a falling market or sell on a rising market additional shares or commodities so as to obtain a more favorable average price