Calculate Geometric Mean in R

Calculate Geometric Mean in R, Geometric mean is the nth root of the product of n values of a set of observations.

Geometric can be expressed as

GM=(x₁, x₂, x₃, ……, x_n)^1/n

The advantage of the geometric mean is

The disadvantageous of the geometric mean is

Calculation is complicated
Cannot be calculated if a set of value contains zero If any one or more values are negative, either geometric mean will not be calculated or an absurd value will be obtained.

The syntax is as follows,

exp(mean(log(x)))

Let’s create a vector for geometric mean calculation.

data <- c(1, 15, 12, 5, 18, 11, 12, 15, 18, 25)

exp(mean(log(data)))
10.37383

As mentioned earlier if a set of values contains zero cannot be executed a geometric mean, However, we can ignore zero values and execute GM.

data <- c(1, 15, 12, 5, 0, 18, 11, 12, 15, 18, 25, 0, -11)

The above data set included negative values and zero.

Let’s make use of the below code for GM calculation.

exp(mean(log(data[data>0])))
10.37383

Let’s create a data frame for geometric mean calculation.

data<- data.frame(x=c(10, 13, 14, 26, 38, 28, 29),
                 y=c(15, 8, 18, 17, 1, 1, 6),
                 z=c(12, 10, 18, 28, 29, 29, 12))

Calculate the geometric mean for x, y, and z.

apply(data[ , c('x', 'y', 'z')], 2, function(x) exp(mean(log(x))))

    x         y         z
20.379699  5.798203 17.992195

Conclusion

Geometric Mean is considered the most suitable average for index numbers.