Is variance the sqaure root or square of standard deviation?

Question

Just a little confused here and unsure weather variance is the square root or the square of a standard deviation?

Answer 1

Hey there!

The variance and standard deviation, have both a similar greek letter known as sigma. Variance is sigma squared and standard deviation is sigma. Since sigma squared is squaring the sigma, varience is squaring the standard deviation. In other words, variance is the square of standard deviation.

Hope it helps!

Answer 2

Standard Deviation is just the square root of Variance

Answer 3

Variance is the square of standard deviation

Answer 4

This is a little difficult to explain but ill give it a shot. Squaring the individual variences causes all the values obtained to be positive. We can then add them all up to obtain our total varience. If we took the square root of all the squared numbers and added them up we would be right back to zero. Remember that x - "x bar" is the difference between the data point and the mean. "x bar" is the average so some values for x (the data point) will be negative and some will be positive. If you calculated correctly, adding them all up will get you back to zero but this doesnt tell you anything. Squaring all the numbers gives us our total varience as we know. But this number is in squared units which doesnt make much sence thinking about it say if we were surveying average ages of college graduated or something like that. Taking the square root of our total varience takes us back to the original units of measure or quantity and gives us our standard deviation which can then be used to tabulate Z scores and statistical inferences and the like. Given you have a normal bell shaped distribution of course :) Hope this helps!

Answer 5

variance is the squared of standard deviation. so if you know variance you can do the square root of that value to get standard deviation, and if you know standard deviation you can square your value to get variance.

Answer 6

hope this helps resolve your question:

http://mathworld.wolfram.com/StandardDeviation.html

Answer 7

sd = sqrt(var)