Calculating the mean is one way to get a measure of the center of the distribution. The formulas for the mean of a population and the mean of a sample are as follows:
Population Mean:
,
where is the ith observation, and N is the population size.
Sample Mean:
,
where is the ith observation, and n is the sample size.
In each formula, we add the values of each data point in the distribution, and divide the sum of the values by the total number of values.