<Dd> the nth root of the product of the data values, where there are n of these . This measure is valid only for data that are measured absolutely on a strictly positive scale . </Dd> <Dd> the reciprocal of the arithmetic mean of the reciprocals of the data values . This measure too is valid only for data that are measured absolutely on a strictly positive scale . </Dd> <Dt> Weighted arithmetic mean </Dt> <Dd> an arithmetic mean that incorporates weighting to certain data elements . </Dd>

X is a mesure of how closely a variable's values cluster around a measure of central tendency