The kth central moment (or moment about the mean) of a data population is:
Similarly, the kth central moment of a data sample is:
In particular, the second central moment of a population is its variance.
Find the third central moment of eruption duration in the data set faithful.
We apply the function moment from the e1071 package. As it is not in the core R library, the package has to be installed and loaded into the R workspace.
> duration = faithful$eruptions # eruption durations
> moment(duration, order=3, center=TRUE)
The third central moment of eruption duration is -0.6149.
Find the third central moment of eruption waiting period in faithful.