http://www.john-weber.com/

HOW TO FIND ONE SAMPLE T CONFIDENCE INTERVALS WITH TI83 CALCULATOR

Steps Key Sequence Screens
1. Set up Stats Tests STAT
  twice
  8 (for TInterval...)
2. Select Input once (if necessary), then ENTER
3. Input mean of SAMPLE once, enter mean of SAMPLE, then ENTER
4. Input standard deviation enter standard devation of SAMPLE, then ENTER
5. Input sample size enter sample size, then ENTER
6. Input confidence level enter confidence level (AS DECIMAL), then ENTER
7. Calculate CI ENTER
In this case the 95% CI is 18.687 to 70.193.