# TI-83 Instructions

## Computing Standard Normal Percentiles

*Z* is the standard normal random variable.

- Find
*c* such that *P*(*Z* < *c*) = *p*.
- Press
`2nd DISTR`

. The `DISTR`

menu title is highlighted.
- Select
`invNorm`

, item #3, or press 3 and skip the next step.
- Press
`ENTER`

. The phrase `invNorm(`

appears in the display.
- Enter the value of
*p*. This number must be between 0 and 1.
- Press
`)`

.
- Press
`ENTER`

. The value of *c* appears in the display.

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