Confidence Interval of Mean


Press STAT and the right arrow twice to select TESTS. Use the down arrow to select 7:Zinterval… 
Press ENTER. Use right arrow to select Stats (summary values rather than raw data). Enter standard deviation, mean, sample size, and
confidence level. Press down arrow to select Calculate and press ENTER. 
Results: The 95% confidence interval for the Normal Distribution is
18.8 to 21.2 when the mean is 20.0 and the sample size is 64. 
Confidence Interval of Proportion


Press STAT and the right arrow twice to select TESTS. Use the down arrow to select Press ENTER. 

Enter number of favorable outcomes, X, sample size, n, and
confidence level. Use down arrow to select Calculate and press ENTER. 

Results: 95% confidence interval is 0.1 to 0.2 when proportion is
0.2 and sample size is 200. 
