T-Test Calculator
Perform a one-sample or two-sample t-test.
Enter your data to calculate the t-statistic, p-value, and determine statistical significance.
T-Test Results
One-Sample T-Test:
t = (x̄ - μ₀) / (s / √n)
Tests whether the sample mean differs from a known or hypothesized value.
Two-Sample T-Test (independent):
t = (x̄₁ - x̄₂) / √(s₁²/n₁ + s₂²/n₂)
Tests whether two groups have different means.
When to use a t-test vs z-test:
- Use a t-test when the population standard deviation is unknown (most real situations)
- Use a z-test when the population standard deviation is known
Interpreting results:
- If p-value < 0.05, the difference is statistically significant
- A larger |t| means a bigger difference relative to the variability