Confidence Interval for a Proportion
To use the applet below, just type in the information into the boxes. Hit enter when you are finished typing. You will need a calculator to work these problems out.
In the applet, the number of successes is labeled "r", so that p = r/n.
You will also need the table below.|
Table for Confidence Intervals |
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| c | 0.8 | 0.9 | 0.95 | 0.99 |
| zc | 1.28 | 1.645 | 1.96 | 2.58 |
Written Exercises
When you have mastered the above tutorial, please answer the following in a few complete sentences
What are the steps for
determining a confidence interval for a proportion?
If your calculations show that a
95% confidence interval for a proportion is [0.4,0.5], is it possible that
the true population proportion is .3?
Information
on finding the confidence interval for a proportion
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