TI-83 Instructions

Computing the Mean and Standard Deviation of a Discrete PDF

**Mean
and Standard Deviation**

- Enter the values of
*X*into list L_{1}. - Enter the probabilities
of
*X*into list L_{2}. - Press STAT. The Stat menu bar appears. The EDIT menu title is highlighted.
- Use the arrow keys to
select the CALC menu title.
The Calc menu appears.
- Use the arrow keys to
select item #1, 1-Var Stats. The phrase 1-Var
Stats
appears in the window.
- Press ENTER.
- Press 2
^{nd}L_{1}. - Enter a comma.
- Press 2
^{nd}L_{2}. - Press ENTER. A list of statistics appears. The first one is the mean of
*X*. - Scroll down to σx. This is the standard deviation of
*X*.

**Variance
(Method 1)**

- Find the standard
deviation, as described above.
- Enter the value of the
standard deviation.
- Press
*x*^{2}. The exponent 2 appears next to the number. - Press ENTER. The result is the variance.

- Find the standard
deviation, as described above.
- Press VARS. The VARS menus appear. The VARS menu title is
highlighted.
- Use the arrow keys to
scroll down to item #5, Statistics....
- Press ENTER. The Statistics menus appear. The XY menu title is
highlighted.
- Use the arrow keys to
scroll down to item #4, σx.
- Press ENTER. The expression σx appears in the
display.
- Press
*x*^{2}. An exponent of 2 appears next to σx. - Press ENTER. The value of the variance appears.