Confidence Interval for Proportion

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Confidence Interval for Proportion

Confidence Interval for Proportion
\[CI=\hat{p}\pm z\sqrt{\frac{\hat{p}(1-\hat{p})}{n}}\]

Variables

CI1 = lower confidence limit
CI2 = upper confidence limit
ph = sample proportion
z = critical z value
n = sample size

Description

What is this formula?

This formula calculates the confidence interval for a population proportion using the normal approximation method.


When to use it

Use this formula when estimating the uncertainty range of a proportion obtained from sample data.


Example

If 60 out of 100 tested products are acceptable, the formula can estimate the confidence interval for the true acceptance proportion.


Applications

Survey analysis, quality control, polling statistics, biomedical studies, manufacturing analysis, and statistical inference.


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