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Both calculators run independently — change the inputs on either side to compare results.
Statistics
Confidence Interval Calculator
Compute the lower and upper bounds of a confidence interval for a population mean using a sample mean, the standard error of that mean, and a critical z-value (1.645 / 1.96 / 2.576 for 90% / 95% / 99% confidence). This is the standard way to report uncertainty around survey results, lab measurements, or any sample-based estimate.
Fill in the required fields to see your result.
Probability
Hypothesis Testing Calculator
Run a one-sample t-test to decide whether a sample mean differs significantly from a hypothesised population mean. Returns 1 (reject the null hypothesis) or 0 (fail to reject) at your chosen confidence level using the one-sample t-statistic and a critical-value lookup.
Fill in the required fields to see your result.
Key differences
| Confidence Interval Calculator | Hypothesis Testing Calculator | |
|---|---|---|
| Category | Statistics | Probability |
| Inputs required | 3 | 6 |
| Result | Lower Bound | Reject Null Hypothesis |
| What it does | Compute the lower and upper bounds of a confidence interval for a population mean using a sample mean, the standard error of that mean, and a critical z-value (1.645 / 1.96 / 2.576 for 90% / 95% / 99% confidence). This is the standard way to report uncertainty around survey results, lab measurements, or any sample-based estimate. | Run a one-sample t-test to decide whether a sample mean differs significantly from a hypothesised population mean. Returns 1 (reject the null hypothesis) or 0 (fail to reject) at your chosen confidence level using the one-sample t-statistic and a critical-value lookup. |