What is standardized variance?
A statistic used as a measure of the dispersion or variation in a distribution or set of data, equal to the square root of the arithmetic mean of the squares of the deviations from the arithmetic mean.
Whats the difference between standard deviation and variance?
Standard deviation looks at how spread out a group of numbers is from the mean, by looking at the square root of the variance. The variance measures the average degree to which each point differs from the mean—the average of all data points.
Is the variance of two independent variables the sum of variances?
I know that the variance of the difference of two independent variables is the sum of variances, and I can prove it. I want to know where the covariance goes in the other case. This is mentioned among the basic properties of variance on http://en.wikipedia.org/wiki/Variance.
How is the variance of the difference related to the sample size?
The variance of the difference is the sum of the variances divided by the sample sizes. This makes sense, hopefully, because according to the central limit theorem, the variance of the sampling distribution of the sample means is the variance divided by the sample size, so what we are doing is add the variance of each mean together.
How are the mean and variance of a combination found?
The mean and variance of the combination can be found from the means and the variances of the original variables. The mean of a sum is the sum of the means. The mean of a difference is the difference of the means. The variance of a sum is the sum of the variances.
Which is the standard deviation of the variance?
Standard deviation is defined as the square root of the variance . The other way around, variance is the square of SD. Total SD = 2√74 = 8.60… This works for any number of independent variables (mark the bold type for independent!)