# standard deviation

## Definitions

### General Science

- noun a measure of the amount by which a set of values differs from the arithmetic mean

### Banking

### Construction

- A statistic, used as a measure of
__dispersion__ in a distribution, that is equal to the square __root__ of the arithmetic average of the squares of the deviations from the mean.

### Economics

- noun the measure of how much a variable changes from its mean

### Electronics

- A statistical measure of the dispersion or
__spread__ around the mean, for a given set, __series__, or population. It is __equal__ to the square __root__ of the __variance__. If a __data set__ has as a bell-shaped distribution, for instance, 68.3% of the __data__ will fall on either side of one __standard__ deviation, __95__.5% within two standard deviation, 99.7% within three, and so on. Its abbreviation is SD. Its __symbol__ is σ.

### Health Economics

- noun a statistical
__term__ to __show__ how far things are different from the normal

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