A basic tool in statistics and probability, variance calculates the spread of a data set, which helps in identifying it for later distributions and samples. A data set's variance comes at the end of a calculation sequence. This series of calculations does not have its own function on the TI83 graphing calculator, but the standard deviation, which is the square root of the variance, does. Finding the variance on the TI83 comes down to pushing a single button at the end of your calculations.

Push the "2nd" button and then push the digit "0" button to access the "Catalog" feature of the calculator.

Push the "LN" button to select the "S" menu. Push the downward facing arrow button until the "stdDev(" option, which stands for standard deviation, is highlighted. Push the "Enter" button to select it. The screen will display the option for data entry.

Push the "2nd" button and then push the "(" button under the "COS" button to access the "{" symbol. Begin entering the numerical data after the symbol, separating each entry by pressing the comma button located under the "SIN" button. When finished with entering your data, push the "2nd" button and then the ")" button under the "TAN" button to access the "}" symbol. Press the ")" button again to terminate the data entry. For example, if the data is {1, 7, 8, 16}, the screen should appear as follows: stdDev({1, 7, 8, 16}).

Push the "Enter" button to perform the calculation. The screen will display the value for the data's standard deviation. Push the "x^2" button located above the "LOG" button to compute the value's square and obtain the variance of the data set.