T Tests
Paired Samples T Test Calculator
Paired Samples T Test Calculator compare paired observations by testing the mean of within-pair differences.
T Tests
Paired Samples T Test Calculator
Compare paired observations by testing the mean of within-pair differences.
Formula
Paired t test: calculate after - before differences, then t = mean difference / (SD of differences / sqrt(n)); df = n - 1.
About the Paired Samples T Test Calculator
Compare paired observations by testing the mean of within-pair differences. T procedures compare means while estimating sampling variability from observed data and using the appropriate Student t degrees of freedom.
How the Paired Samples T Test Calculator Works
Paired t test: calculate after - before differences, then t = mean difference / (SD of differences / sqrt(n)); df = n - 1.
The calculation runs in your browser. Submitted values are validated for the required numeric range, data shape, units, and method-specific restrictions before a result is shown.
Required Inputs
- Before data (required)
- After data (required)
- Alpha (required)
- Alternative hypothesis (required) Options: Two-tailed, After - before is greater, After - before is less
Results Reported
The result panel shows the final answer together with the intermediate quantities needed to audit the calculation. Depending on this method, reported values include:
nmean_differencesd_differencestandard_errordft_statisticp_valuecohens_dzdecision
Paired Samples T Test Calculator Example
Paste the sample data, click Calculate, and compare the detailed table with the expected output.
| Input | Example value |
|---|---|
| Before data | 10,12,9,11,13 |
| After data | 12,13,11,12,15 |
| Alpha | 0.05 |
| Alternative hypothesis | two |
How to Use the Calculator
- Confirm that the calculator title and method match the quantity, test, conversion, or planning question you need to solve.
- Enter values with compatible units and the requested sample, group, matrix, count, date, or option format.
- Select Example Data to inspect a valid input layout, or enter your own values and select Calculate.
- Review the result table, formula, worked substitutions, warnings, and interpretation rather than using only the headline number.
- Use Copy Result or Download CSV when you need a reusable record of the displayed calculation.
Understanding the Result
Choose paired, pooled independent, Welch, or one-sample analysis to match the design; these methods are not interchangeable.
Keep the entered values, units, selected options, and any warning shown beside the result. For a hypothesis test, report the statistic, degrees of freedom where applicable, p-value, alpha level, effect size, and decision. For an estimate or conversion, report the formula convention and final unit.
Accuracy and Limitations
The calculator keeps full browser precision during calculation and rounds only for display. Accuracy still depends on correct inputs and on whether the displayed model represents the real problem. Educational calculators cannot replace required professional review, current official rules, field measurements, laboratory methods, or specialist statistical software where those are necessary.
Frequently Asked Questions
What does the Paired Samples T Test Calculator calculate?
Compare paired observations by testing the mean of within-pair differences.
Which formula does the Paired Samples T Test Calculator use?
Paired t test: calculate after - before differences, then t = mean difference / (SD of differences / sqrt(n)); df = n - 1.
Is this calculator free to use?
Yes. Visitors can use it publicly through the shortcode page.
Does the calculator store visitor data?
No. Calculations run in the browser and do not store visitor data.