The geometric mean of the observations x₁, x₂, ……, x_n  is defined as

For simple frequency distribution,

For grouped frequency distribution, x1 is taken as class mark.

NOTE: 1. The logarithm of the G.M. of a variate is the A.M. of its logarithm.

1. G.M. = 0 iff a single variate value is zero.
2. G.M. is not used if any variate value is negative.

Example 2. Find the G.M. of the following distribution

Solution. Here N = No. of days = 15.