Yes, sigma squared (σ²) represents the variance of a population in statistics. Variance measures the dispersion of a set of values around their mean, and it is calculated as the average of the squared differences from the mean. In summary, σ² is simply the symbol used to denote variance in statistical formulas.
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Equal in Variance
because of two things- a) both positive and negative deviations mean something about the general variability of the data to the analyst, if you added them they'd cancel out, but squaring them results in positive numbers that add up. b) a few larger deviations are much more significant than the many little ones, and squaring them gives them more weight. Sigma, the square root of the variance, is a good pointer to how far away from the mean you are likely to be if you choose a datum at random. the probability of being such a number of sigmas away is easily looked up.
The mean deviation (also called the mean absolute deviation) is the mean of the absolute deviations of a set of data about the data's mean. The standard deviation sigma of a probability distribution is defined as the square root of the variance sigma^2,
Standard deviation = square root of variance.
Square the standard deviation and you will have the variance.