Mean and standard deviation in LaTeX

In a lab report you usually give the mean of a series of measurements and its uncertainty. The bar over the mean symbol is \bar{x}, and the root of a sum of squares combines \sqrt and \sum.

Arithmetic mean

\bar{x} = \frac{1}{n} \sum_{i=1}^{n} x_i

\bar{x} = \frac{1}{n} \sum_{i=1}^{n} x_i

Standard deviation

s = \sqrt{\frac{1}{n-1} \sum_{i=1}^{n} (x_i - \bar{x})^2}

s = \sqrt{\frac{1}{n-1} \sum_{i=1}^{n} (x_i - \bar{x})^2}

Uncertainty of the mean (type A)

u(\bar{x}) = \frac{s}{\sqrt{n}}

u(\bar{x}) = \frac{s}{\sqrt{n}}

Common mistakes

\overline instead of \bar for a single letter: the bar comes out too long. Keep \overline for longer expressions.
Dividing by n instead of n - 1 for the sample standard deviation.

Mean and standard deviation in LaTeX

Arithmetic mean

Standard deviation

Uncertainty of the mean (type A)

Common mistakes

See also