Variance is a statistical measure that tells us how measured data vary from the average value of the set of data.

In other words, variance is the mean of the squares of the deviations from the arithmetic mean of a data set.

More About Variance

Variance is the square of the standard deviation.
The formula for variance is

Video Examples: What is Variance in Statistics?

Solved Example on Variance

Ques: Find the variance of the data set {1, 2, 3, 4, 10}.

Choices:

A. 10
B. 9
C. 8
D. 7
Correct Answer: A

Solution:

tep 1: The mean of the data set {1, 2, 3, 4, 10} is [Use the formula for mean.]
Step 2: The standard deviation of the data set is
[Use the formula for mean.]
Step 3:
Step 4: The variance of the data set is [Substitute ]