means
Student's t-test
Compare two independent group means when equal variances are defensible.
Requirements
- continuous outcome
- one two-level group
- similar variances
Avoid when
- unequal variances
- paired data
- three or more groups
Formula
t = (x̄₁ − x̄₂) / (sₚ √(1/n₁ + 1/n₂))
Interpretation
Same estimand as Welch's t-test, but pooled variance is used.
Worked example
Compare mean reaction time between two independent groups when equal variances are justified.
Open example datasets