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The arithmetic mean is the average of a group of numbers and is computed by summing all numbers and dividing by the number of numbers. The arithmetic mean is also usually just called the mean.

In these lessons, we will distinguish between the population mean and sample mean.

Related Topics: More Statistics Lessons

A population is a collection of persons, objects or items of interest.

A sample is a portion of the whole and, if properly taken, is representative of the whole.

The population mean is represented by the Greek letter *mu *. It is given by the formula

The capital Greek letter sigma is commonly used in mathematics to represent a summation of all the numbers in a grouping.

*N* is the number of terms in the population.

The sample mean is represented by . It is given by the formula

*n *is the number of terms in the sample.

How to find the Sample Mean.

Sample mean versus population mean

The following video highlights the difference between the mean of a sample and the mean of a population.

Arithmetic Mean for Samples and Populations.

Describes the calculations for the sample and population means.