In statistics, the standard deviation is the square root of the variance; it's one way of showing how data varies, or how it is spread out in a distribution. The standard deviation tells you how much of the data lies within a certain area. A standard deviation can be tricky to calculate by hand, as it requires multiple steps. The TI84 Plus graphing calculator can eliminate those steps and calculate the standard deviation in just a few keystrokes.

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

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

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

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}).

Press the "Enter" key. The calculator will return the standard deviation for the entered numbers.

#### TL;DR (Too Long; Didn't Read)

If you get an error, make sure you entered both sets of brackets to get your answer: the brackets are commonly overlooked.