Variance | R Tutorial (2024)

The variance is a numerical measure of how the data values is dispersed around themean. In particular, the sample variance is defined as:

Similarly, the population variance is defined in terms of the population mean μand population size N:

Problem

Find the sample variance of the eruption duration in the data set faithful.

Solution

We apply the var function to compute the sample variance of eruptions.

>duration=faithful$eruptions#theeruptiondurations
>var(duration)#applythevarfunction
[1]1.3027

Answer

The sample variance of the eruption duration is 1.3027.

Exercise

Find the sample variance of the eruption waiting periods in faithful.