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HOW TO FIND CONFIDENCE INTERVALS WITH TI83 CALCULATOR

Steps Key Sequence Screens
1. Set up Stats Tests STAT
  twice
  7 (for ZInterval...)
2. Select Input once then ENTER
3. Input standard deviation once, enter standard devation of POPULATION (if known, otherwise use standard devation of sample), then ENTER
4. Input mean of SAMPLE enter mean 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 90% CI is 3.0101 to 3.3899.