Paired t-test
= Paired t-test
{title2=$t=(\bar d-d_0)/(s_d/\sqrt n)$}
A one-sample <Student t-test> on independent pairs' differences $d_i$. It tests a specified mean difference $d_0$, using the <standard deviation> of those differences rather than treating both measurements in a pair as independent. Exact small-sample inference assumes normally distributed differences.