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Variance measures how data values spread around the mean. With a TI‑84 graphing calculator, you can calculate the variance instantly by first obtaining the standard deviation (SD) and then squaring it, since variance = SD².

Step 1

Press STAT (column 3, row 3) followed by ENTER (column 5, row 10) to open the List Editor.

Step 2

Enter the data set in the L1 column:

100
200
300
400
500

Type each number and press ENTER after each entry.

Step 3

Exit the List Editor by pressing 2nd (column 1, row 2) then MODE (column 5, row 12).

Step 4

Return to the STAT menu, move the cursor to CALC using the right arrow, and prepare for the next step.

Step 5

Press ENTER twice to select 1‑Var Stats. The calculator will display a series of statistics. The sample standard deviation appears four rows below the mean and is labeled Sx. For the example data, Sx should be 158.11. If it differs, double‑check your entries.

Step 6

Press VARS (column 4, row 4), choose option 5 (Stats), and hit ENTER to access the parameter menu.

Step 7

Select option 3 (Standard Deviation) to use the SD as a variable in a new calculation. Press ENTER.

Step 8

Press X² (column 1, row 6) to square the selected SD, then press ENTER. The result is the variance: 25,000, confirming that variance = (158.11)².