In statistics and probability theory, standard deviation (represented by the symbol σ) shows how much variation or "dispersion" exists from the average (mean, or expected value).
A simpler explanation of standard deviation, written by a former math-major-turned-journalist who likes to explain math to people don't understand or just plain hate it.
Standard Deviation. Lower case sigma means 'standard deviation'. Capital sigma means 'the sum of'. x bar means 'the mean' The standard deviation measures the spread of the data ...
Standard Deviation and Variance. Deviation just means how far from the normal. Standard Deviation. The Standard Deviation is a measure of how spread out numbers are.
Standard deviation is a number used to tell how measurements for a group are spread out from the average (mean), or expected value. A low standard deviation means that most of ...
This is part of HyperStat Online, a free online statistics book.
2008/9 Schools Wikipedia Selection. Related subjects: Mathematics. In probability and statistics, the standard deviation of a probability distribution, random variable, or ...
The standard deviation sigma of a probability distribution is defined as the square root of the variance sigma^2, sigma = sqrt(<x^2>-<x>^2) (1) = sqrt(mu_2^'-mu^2), (2) where ...
Standard Deviation - Definition of Standard Deviation on Investopedia - 1. A measure of the dispersion of a set of data from its mean. The more spread apart the data, the ...
The interval between the upper and lower bands and the middle band is determined by volatility, typically the standard deviation of the same data that were used for the average.
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