How To Calculate Confidence Interval For Sample Proportion

Calculating the confidence interval for a sample proportion is crucial in statistics to estimate the population proportion within a certain degree of confidence. This tool will guide you through the process.

1. Enter your sample size, proportion, and desired confidence level.
2. Click ‘Calculate’.
3. View your results and chart below.

The formula used is:

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

Where:

• z is the z-score based on your confidence level.
• p is the sample proportion.
• n is the sample size.

Comparison of Confidence Intervals

Sample Size	Sample Proportion	90% CI	95% CI	99% CI

• Always use an appropriate sample size for accurate results.
• Consider the confidence level based on your needs.
• Remember, a larger confidence interval indicates less precision.

What is a confidence interval?

A confidence interval is a range of values around a sample statistic (like a mean or proportion) within which we are confident that the true population parameter lies.

For more information, see these authoritative sources:

• CDC: Confidence Intervals
• Introductory Statistics (OpenStax)