How to Calculate Variance

Finding variance in a data set doesn't require a mathematician. Impress your employer or teacher with your knowledge of statistics without the headache of complicated computations or formulas.

You will need

  • Set of data
  • Basic math computation skills
  • Graphing calculator

Step 1 Find the sum of the numbers Add all of the numbers together to find the sum.

Step 2 Divide the sum Divide the sum of the data by the number of values in the set to find the mean, or average.

Step 3 Subtract the mean from each value Subtract the mean, or average, from each value in the data set and then square the difference, or multiply the result by itself.

Step 4 Add the squared results Add all of the squared results together using a graphing calculator.

Step 5 Divide by the number of values Divide by the number of values in the data set. This will give you the variance of the data. Use this value to compare variances, make predictions, and show off how well you analyzed the data.