# Making Deviation Standard

### Resources for this lesson:

> Glossary

> Calculator Resources

> Teacher Resources: Instructional Notes

Andrew and Khalid are still confused about how to calculate the standard deviation. Justyce suggests they watch a short video for one more example. If you are still confused, take time to watch the video.

Sample standard deviation and bias (from Khan Academy)

There is a basic formula for finding the standard deviation. Follow each step below to discover this formula.

**STEP 1:**Calculate the mean of the data. The symbol used for mean is*x*.**STEP 2:**Subtract each data point from the mean, square the differences, and add the differences together. The symbol used for each data point is for*n*data points.

## Check Your Understanding

**STEP 3:**Divide the sum by the number of data points.

## Check Your Understanding

**STEP 4:**Take the square root of the quotient arrived at in Step 3.

This is the formula for finding the standard deviation of a set of data.