t's the same thing really, as you say the variance is the square of the standard deviation. The latter has the advantage that it is in the same units as the mean, which makes interpretation easy. For example, if you are measuring a length in cm, the standard deviation would be expressed in cm but the variance would be in (cm)^2

One reason for the use of the variance is that the variance of the sum (or the difference) of uncorrelated random variables is the sum of their variances.

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Ashima Joshi

Fri, 05/17/2013 - 16:42

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## t's the same thing really, as

t's the same thing really, as you say the variance is the square of the standard deviation. The latter has the advantage that it is in the same units as the mean, which makes interpretation easy. For example, if you are measuring a length in cm, the standard deviation would be expressed in cm but the variance would be in (cm)^2

One reason for the use of the variance is that the variance of the sum (or the difference) of uncorrelated random variables is the sum of their variances.

Ashima