Paired T-Test Sample Size Calculator
FreeCalculate the sample size (number of pairs) needed to detect a mean difference in paired or matched observations.
Study Parameters
Results
Required Sample Size
32
Achieved Power
80.7%
Effect Size
0.500
Method: Two-sided paired t-test
Number of pairs32
Cohen's d_z0.500
- •Paired (matched) observations
- •Normally distributed differences (or large sample via CLT)
- •Two-sided hypothesis test
Formula
n = (z_{alpha/2} + z_beta)^2 * sigma_d^2 / delta^2
References
- Chow SC, Shao J, Wang H (2008). Sample Size Calculations in Clinical Research, 2nd ed. Chapman & Hall/CRC.