## How to Find a Standard Deviation on a TI 83 Calculator

Technically, the standard deviation is defined as the square root of the variance. But where the standard deviation comes in handy is when it is used to describe part of a distribution. Standard deviations give us an idea of how much data is contained within a certain area of a distribution curve. This information is especially useful when using normal distribution curves (which you’ll, no doubt, learn about during your statistics course).

Sample problem: Find the standard deviation for the heights of the top 12 buildings in London, England. The heights, (in feet) are: 800, 720, 655, 655, 625, 600, 590, 529, 513, 502, 502, 502.

Step 1: Enter the above data into a list. Press the button and then press . Enter the first number (800), and then press . Continue entering numbers, pressing after each entry.

Step 2: Press .

Step 3: Press the right arrow button (the arrow keys are located at the top right of the keypad) to select Calc.

Step 4: Press to highlight 1-Var Stats.

Step 5: Press again to bring up a list of stats. The standard deviation (Sx) for the above list of data is 96.57 feet (rounded to 2 decimal places).