# standard deviation

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Related to standard deviation: variance

## standard deviation

[′stan·dərd ‚dē·vē′ā·shən] (statistics)

The positive square root of the expected value of the square of the difference between a random variable and its mean.

McGraw-Hill Dictionary of Scientific & Technical Terms, 6E, Copyright © 2003 by The McGraw-Hill Companies, Inc.

## standard deviation

see MEASURES OF DISPERSION.Collins Dictionary of Sociology, 3rd ed. © HarperCollins Publishers 2000

## standard deviation

(statistics)(SD) A measure of the range of values in a set of
numbers. Standard deviation is a statistic used as a measure
of the dispersion or variation in a distribution, equal to the
square root of the arithmetic mean of the squares of the
deviations from the arithmetic mean.

The standard deviation of a random variable or list of numbers (the lowercase greek sigma) is the square of the variance. The standard deviation of the list x1, x2, x3...xn is given by the formula:

sigma = sqrt(((x1-(avg(x)))^2 + (x1-(avg(x)))^2 + ... + (xn(avg(x)))^2)/n)

The formula is used when all of the values in the population are known. If the values x1...xn are a random sample chosen from the population, then the sample Standard Deviation is calculated with same formula, except that (n-1) is used as the denominator.

[

["Barrons Dictionary of Mathematical Terms, second edition"].

The standard deviation of a random variable or list of numbers (the lowercase greek sigma) is the square of the variance. The standard deviation of the list x1, x2, x3...xn is given by the formula:

sigma = sqrt(((x1-(avg(x)))^2 + (x1-(avg(x)))^2 + ... + (xn(avg(x)))^2)/n)

The formula is used when all of the values in the population are known. If the values x1...xn are a random sample chosen from the population, then the sample Standard Deviation is calculated with same formula, except that (n-1) is used as the denominator.

[

**dictionary.com**].["Barrons Dictionary of Mathematical Terms, second edition"].

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**foldoc.org**)## standard deviation

In statistics, the average amount a number varies from the average number in a series of numbers.Copyright © 1981-2019 by

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