The mean of an observation variable is a numerical measure of the central location of the data values. It is the sum of its data values divided by data count.
Hence, for a data sample of size n, its sample mean is defined as follows:
Similarly, for a data population of size N, the population mean is:
Find the mean eruption duration in the data set faithful.
We apply the mean function to compute the mean value of eruptions.
> mean(duration) # apply the mean function
The mean eruption duration is 3.4878 minutes.
Find the mean eruption waiting periods in faithful.