TI-83 Instructions

Computing Standard Normal Percentiles

Z is the standard normal random variable.

Find c such that P(Z < c) = p.

1. Press 2nd DISTR. The DISTR menu title is highlighted.
2. Select invNorm, item #3, or press 3 and skip the next step.
3. Press ENTER. The phrase invNorm( appears in the display.
4. Enter the value of p. This number must be between 0 and 1.
5. Press ).
6. Press ENTER. The value of c appears in the display.

Find c such that P(Z > c) = p.

1. Compute 1 − p.
2. Use the above procedure to find c such that P(Z < c) = 1 − p.