The Geometric Mean is a "summary" statistic useful when the measurement scale is not linear; it is computed as:

G = (x1 *x2 *...*xn )1/n

where

n is the sample size.

STATISTICA calculates the geometric mean via the logarithm (log):

log(G) = {S[log(xi)]}/n

where

n is the sample size.

See also, Ordinal Descriptive Statistics.