How to Find Standard Deviation on a TI 84 Plus

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In statistics, standard deviation is the square root of the variance. It provides a way of showing how data varies or how it is spread out in a distribution. Standard deviation tells you how much of the data lies within a certain area. Standard deviation can be tricky to calculate by hand, as it requires multiple steps. The TI 84 Plus graphing calculator eliminates those steps and calculates standard deviation with just a few keystrokes.

  1. Select the Catalog

  2. Click on the "2nd" key and then click on "0." This selects the catalog.

  3. Scroll to Letter S

  4. Press the "LN" button to scroll through the catalog to the letter "s."

  5. Scroll to srdDev(

  6. Press the "down arrow" key to scroll until you reach "stdDev(." Press "Enter."

  7. Complete Statement

  8. Complete the statement with an open curly bracket – the "{" sign – and the numbers for which you want to find the standard deviation, followed by a closing curly bracket and closing parenthesis. For example: stdDev({1,2,3,4,5,6}).

  9. Press Enter

  10. Press the "Enter" key. The calculator returns the standard deviation for the entered numbers.


    • If you get an error, make sure you entered both sets of brackets to get your answer. This part is commonly overlooked.


About the Author

Stephanie Ellen teaches mathematics and statistics at the university and college level. She coauthored a statistics textbook published by Houghton-Mifflin. She has been writing professionally since 2008. Ellen holds a Bachelor of Science in health science from State University New York, a master's degree in math education from Jacksonville University and a Master of Arts in creative writing from National University.