Population Confidence Interval For Proportions Calculation

Population confidence interval for proportions calculation is a statistical method used to estimate the range within which the true population proportion lies with a certain degree of confidence.

1. Enter the population size.
2. Enter the proportion of the population that has a certain characteristic.
3. Select the desired confidence level.
4. Click ‘Calculate’.

The formula used is:

margin_of_error = z * sqrt((p * (1 - p)) / n)

Where:

• z is the z-score based on the chosen confidence level.
• p is the proportion.
• n is the population size.

Confidence Intervals for Different Confidence Levels

Confidence Level	Z-Score
90%	1.645
95%	1.96
99%	2.576

• Always use the correct z-score for your desired confidence level.
• Ensure your population size is large enough for the calculation to be valid.

What is a z-score?

A z-score is a measure of how many standard deviations an element is from the mean.

CDC Statistics – UK Office for National Statistics – US Census Bureau