How to Calculate Standard Deviations on Ti-84s

Standard deviation is a statistical tool that evaluates the consistency of data. A standard deviation is a root of the data's variance, which calculates the differences between the individual numbers of a set of data and the average of those numbers, squares those differences and then averages the squares. The TI-84, TI-84 Plus, and TI-84 Plus Silver Edition graphing calculators make short work of these calculations with a programmed function that directly calculates the standard derivation.

Things You'll Need

• TI-84, TI-84 Plus or TI-84 Plus Silver Edition graphing calculator

Instructions

1. Turn your calculator on. Press the blue "2nd" key at the top-left of the keypad, then press the "0" key.

2. Press the "LN" key on the left-hand side of the keypad, then press the down arrow key located in the top right corner of the keypad to scroll down to the standard deviation option, labeled "stdDev(" then press "Enter". The "stdDev(" prompt will appear on the screen.

3. Press the "2nd" key, then press the "(", or left parenthesis key, located above the number "8" key to obtain the left bracket symbol "{". Enter the numbers, separating them with commas by pressing the "," key above the number "7" key. End the statement by pressing the "2nd" key then the ")", or right parenthesis key, to enter the right bracket, "}", then press the ")" key again to enter the ending parenthesis.

4. Press "Enter". The screen will display the standard deviation for your data.

References

• Scribd: TI-84 Plus Guidebook
• University of Florida Department of Statistics: Getting the Standard Deviation from Your Calculator
• Wolfram MathWorld: Standard Deviation
• Quick MBA: Standard Deviation and Variance

Resources

• EasyCalculation.com: Standard Deviation Calculator