TI-83 Instructions

Computing the Mean and Standard Deviation of a Discrete PDF

Mean and Standard Deviation

1. Enter the values of X into list L1.
2. Enter the probabilities of X into list L2.
3. Press STAT.  The Stat menu bar appears.  The EDIT menu title is highlighted.
4. Use the arrow keys to select the CALC menu title.  The Calc menu appears.
5. Use the arrow keys to select item #1, 1-Var Stats.  The phrase 1-Var Stats appears in the window.
6. Press ENTER.
7. Press 2nd L1.
8. Enter a comma.
9. Press 2nd L2.
10. Press ENTER.  A list of statistics appears.  The first one is the mean of X.
11. Scroll down to σx.  This is the standard deviation of X.

Variance (Method 1)

1. Find the standard deviation, as described above.
2. Enter the value of the standard deviation.
3. Press x2.  The exponent 2 appears next to the number.
4. Press ENTER.  The result is the variance.

# Variance (Method 2)

1. Find the standard deviation, as described above.
2. Press VARS.  The VARS menus appear.  The VARS menu title is highlighted.
3. Use the arrow keys to scroll down to item #5, Statistics....
4. Press ENTER.  The Statistics menus appear.  The XY menu title is highlighted.
5. Use the arrow keys to scroll down to item #4, σx.
6. Press ENTER.  The expression σx appears in the display.
7. Press x2.  An exponent of 2 appears next to σx.
8. Press ENTER.  The value of the variance appears.