How to use the paired t-statistic calculator
Find the t statistic and degrees of freedom for paired measurements from the mean and spread of differences. Enter mean of differences, standard deviation of differences, number of pairs in the fields above; the test statistic t, degrees of freedom are computed instantly and plotted on the chart so you can see how the answer changes.
Common searches this calculator answers include “paired t test”, “before and after comparison”, “t statistic from differences”, “calculate paired t-statistic”, “find test statistic t”.
Formula
Variables
- md — Mean of differences (units)
- sd — Standard deviation of differences (units)
- n — Number of pairs
Worked example
With mean of differences = 2.5 units, standard deviation of differences = 4 units, number of pairs = 25, the calculator gives test statistic t ≈ 3.125; degrees of freedom ≈ 24.
Frequently asked questions
What is the paired t-statistic calculator used for?
Find the t statistic and degrees of freedom for paired measurements from the mean and spread of differences. It helps with questions such as “paired t test”, “before and after comparison”, “t statistic from differences”.
What is the formula for the paired t-statistic calculation?
Test statistic t = md / (sd / √(n)). Degrees of freedom = n-1. Here md is mean of differences (units), sd is standard deviation of differences (units), n is number of pairs.
What inputs do I need for the paired t-statistic calculator?
You need mean of differences in units, standard deviation of differences in units, number of pairs. Each field is pre-filled with a typical example so you can see how the result responds as you edit the numbers.
How do I use the paired t-statistic calculator?
Type values into the input fields. Results and the chart update instantly. Use Reset to restore the example values, Copy results to paste them elsewhere, or Share to copy a link that preserves your inputs.
Is the paired t-statistic result exact?
Calculations use standard formulas and double-precision arithmetic, then display about seven significant figures. Real-world measurements carry uncertainty, so treat results as estimates unless your inputs are exact.