Arithmetic mean

The arithmetic mean is defined as the sum of all the members of a set of data divided by the number of items in the set. If the set used is a population, then we speak of the population mean. When the set is a sample, we call the statistic a sample mean.

We denote the set of data by X = {x₁, x₂, ..., x_n}. The symbol µ is used to denote the arithmetic mean of a population. We use the name of the variable, X, with a horizontal bar over it as the symbol for a sample mean. We read this symbol as "X Bar".

• Arithmetic mean = ( x₁ + x₂ + ... + x_n ) / n

see also geometric mean, harmonic mean, arithmetic-geometric mean, weighted mean, variance, central tendency

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