An R Introduction to Statistics

Standard Deviation

The standard deviation of an observation variable is the square root of its variance.

Problem

Find the standard deviation of the eruption duration in the data set faithful.

Solution

We apply the sd function to compute the standard deviation of eruptions.

> duration = faithful$eruptions    # the eruption durations 
> sd(duration)                     # apply the sd function 
[1] 1.1414

Answer

The standard deviation of the eruption duration is 1.1414.

Exercise

Find the standard deviation of the eruption waiting periods in faithful.