Math & Science
T-Test Calculator
Compare means between groups
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Frequently asked questions
Independent vs paired?
Use paired for before/after measurements on same subjects. Independent for different groups.
One-tailed vs two-tailed?
One-tailed if you predict direction of difference. Two-tailed if either direction possible.
What is effect size?
Cohen's d measures practical significance. 0.2=small, 0.5=medium, 0.8=large.
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About this tool
This T-Test Calculator turns your inputs into practical results. Provide Group 1 Data, Group 2 Data, and Test Type to calculate P-Value and T-Statistic.
Adjust values to compare scenarios and see how sensitive the result is. The calculation uses the numbers as entered, so double-check units and expect small differences from rounding in the displayed totals.