# Exploring a Single Confidence Interval for a Proportion

- Author:
- Steve Phelps

- Topic:
- Confidence Interval

The applet below allows you to explore a single confidence interval for a proportion (a 1-proportion z-interval). Set the population proportion,
sample size, and confidence level using the sliders. There is 1 confidence intervals at your chosen confidence level, based on 1 random
sample of your chosen sample size, from a population with your chosen proportion.
Once you set your sliders, click on the NEW SAMPLE button to create new confidence intervals based on a new sample for your chosen
settings. On average, the percentage of confidence intervals that contain the population proportion will be equal to the chosen confidence level.
You will notice that larger sample sizes produce shorter confidence intervals (why?).
You will notice that larger confidence levels produce longer confidence intervals (why?)