Calculate an unweighted sample proportion and its plug-in binomial standard error from observed success and trial counts.
How to use this tool
- Choose the event or model and review the assumptions below.
- Enter the labeled inputs.
- Select Calculate and read the labeled outputs.
- Change an input and calculate again; Reset restores the example inputs.
Calculation method
p̂=x/n. Plug-in binomial standard error=√[p̂(1−p̂)/n].
Assumptions and limits
An unweighted sample proportion with integer counts and n>0. The standard error uses an independent, constant-probability Bernoulli model. No confidence interval, survey weighting, finite-population correction or design effect is implied.
Worked example
For 42 successes in 100 trials, p-hat is 0.42 and the plug-in standard error is approximately 0.04936. No confidence interval is produced.
Worked reading and practical questions
Browse Statistics calculators or explore other tools on the GreenCalc homepage.
Frequently asked questions
What does this calculator assume?
An unweighted sample proportion with integer counts and n>0. The standard error uses an independent, constant-probability Bernoulli model. No confidence interval, survey weighting, finite-population correction or design effect is implied.
How do I enter and update the inputs?
Use the labeled fields, then select Calculate. Percent fields use 0 to 100. After editing, calculate again; Reset restores the example inputs.