Stat Unit

The mean is the first descriptive measure for which we actually have a formula:

	where:

When computing the mean of a population, we label it with the Greek letter m (pronounced mu).

When computing the mean of a sample, we label it with the Latin letter X with a bar across the top (pronounced X bar).

While the formula for computing the mean is the same either for a population or sample, the use of different letters indicate whether the computed value is a parameter or a statistic.