Question

What is difference between standard deviation and variance?

Answer 1

Variance and Standard Deviation

• When we consider the variance, we realize that there is one major drawback to using it. When we follow the steps of the calculation of the variance, this shows that the variance is measured in terms of square units because we added together squared differences in our calculation. For example, if our sample data is measured in terms of meters, then the units for a variance would be given in square meters.

• In order to standardize our measure of spread, we need to take the square root of the variance. This will eliminate the problem of squared units, and gives us a measure of the spread that will have the same units as our original sample.

• There are many formulas in mathematical statistics that have nicer looking forms when we state them in terms of variance instead of standard deviation.

Answer 2

Answer:

The standard deviation is the square root of the variance. The standard deviation is expressed in the same units as the mean is, whereas the variance is expressed in squared units, but for looking at a distribution, you can use either just so long as you are clear about what you are using