In mathematics, the root mean square (abbrev. RMS, RMS or rms) of a set of numbers is the square root of the set's mean square.[1] Given a set , its RMS is denoted as either or . The RMS is also known as the quadratic mean (denoted ),[2][3] a special case of the generalized mean. The RMS of a continuous function is denoted and can be defined in terms of an integral of the square of the function.
The RMS of an alternating electric current equals the value of constant direct current that would dissipate the same power in a resistive load.[1] In estimation theory, the root-mean-square deviation of an estimator measures how far the estimator strays from the data.