Understand sampling uncertainty
How confidence intervals express uncertainty
Confidence Interval for Paired Means. A confidence procedure adds model-based uncertainty around an estimate. Wider confidence levels and noisier or smaller samples generally produce wider intervals.
1Compute the sample estimate2Calculate its standard error3Apply the stated confidence procedure
Method used
d̄±t* sd/√n.
The interval describes the direction and plausible magnitude of the average paired change.
What the result cannot establish
A 95% confidence interval does not mean there is a 95% probability that a fixed parameter lies inside this realized interval. The 95% describes long-run coverage of the procedure under its assumptions.
Assumption: Pairs must align, differences should be independent across units, and the t model must be suitable for their mean.
Quick guide
How to use this calculator
- Enter the observations, probabilities, model parameters, or summary statistics requested by the visible labels.
- Keep every value on the same scale and confirm that the selected sampling relationship, distribution, and tail convention match the question you are investigating.
- Read the result together with its assumptions and interpretation. Statistical output summarizes uncertainty under a model; it does not repair biased data or establish causation.
Calculation method
How the confidence interval for paired means calculator works
d̄±t* sd/√n.
The interval describes the direction and plausible magnitude of the average paired change.
Worked example
Confidence Interval for Paired Means example
Differences 2, 3, 1, 4 center the interval at a mean change of 2.5.
d̄±t* sd/√n.
Supported inputs
Precision and limits
Model and design
Pairs must align, differences should be independent across units, and the t model must be suitable for their mean.
Numerical scope
Inputs use double-precision numerical methods with guarded domains. Datasets accept up to 10,000 finite plain-decimal values. Extremely large parameters or probabilities deep in a numerical tail may require specialist statistical software.
Interpretation
The interval describes the direction and plausible magnitude of the average paired change.
Decision boundary
The calculator does not validate how data were collected, diagnose dependence or bias, choose a scientifically meaningful effect, or replace review by a qualified statistician for consequential research, medical, regulatory, safety, or policy decisions.
Privacy
Entered values and calculated results stay in this browser and are not sent to an analytics service.
Continue calculating
Related calculators