How to Calculate Sigma?

Learn how to calculate Standard Deviation / Sigma (σ).

Standard Deviation Calculation

Standard Deviation in mathematics is a measure of how much the data of a group differ from the mean value for the group. It is expressed as SD, or Greek letter sigma σ. Hence, standard deviation is also termed as sigma.
Let us learn here how to calculate sigma σ for a set of data with a simple example.

Formula Used:


Step 1: Let us consider a data set : 6, 1, 4, 3, 10, 8

Step 2: Find the mean of the data set,
6+1+4+3+10+8 / 6 = 32 / 6 = 5.333

Step 3: Subtract the mean from each individual value and square the result.
(6 - 5.333)² = (0.667)² = 0.444889
(1 - 5.333)² = (-4.333)² = 18.774
(4 - 5.333)² = (-1.333)² = 1.776889
(3 - 5.333)² = (-2.333)² = 5.442889
(10 - 5.333)² = (4.667)² = 21.780889
(8 - 5.333)² = (2.667)² = 7.112889

Step 4: Find the mean of the above squared differences.
0.444889 + 18.774 + 1.776889 + 5.442889 + 21.780889 + 7.112889 / 6 = 55.332445 / 6 = 9.222

Step 5: Find the square root of the above result to get sigma σ value,
²âˆš9.222 = 3.036
sigma σ = 3.036

Related Topics