TI-83 Instructions

Computing a Weighted Mean

• Enter the data values (x) into list L1.
• Enter the weights (w) into list L2.

Method 1 (Special keys)

1. Press STAT.
2. Use the arrow keys to select the CALC menu title.
3. Select item #1, 1-Var Stats.
4. Press 2nd L1.
5. Enter a comma.
6. Press 2nd L2.
7. Press ENTER. A list of statistics appears. The first one is the weighted mean.

Method 2 (By the formula)

1. Press 2nd L1.
2. Press × (multiply).
3. Press 2nd L2.
4. Press STO.
5. Press 2nd L3.
6. Press ENTER. This stores the products xw in list L3.
7. Enter the expression sum(L3) in the display. (See Computing a Mean.)
8. Press ÷ (divide).
9. Enter the expression sum(L2) in the display.
10. Press ENTER. The weighted mean is displayed.