Calculator
Enter the values below. Every quantity identifies its unit or meaning.
observations
%
%
Formula / method
E = z × √[p(1−p)/n]. This is the normal approximation.
E = z × √[p(1−p)/n]. This is the normal approximation.
How to use this calculator
What to enter
Enter or select the following as requested: Sample size; Observed proportion; Confidence level. Follow the units, valid ranges, examples, and options displayed beside each field.
What the result means
The statistical result depends on the sample sizes, observed values, variability, confidence level, effect size, and assumptions selected. Check independence, sampling method, distribution assumptions, and whether the inputs represent the same population and measurement scale.
When to use it
Use this to plan or interpret a statistical analysis. Treat the output in the context of the study design and data quality; it does not remove bias from a non-representative sample.