T test of mean
From OPOSSEM
<math>t = \frac {\bar{y}-\mu_0}{s_\bar{y}}</math>, where <math>\mu_0 </math> is the test value and <math>\text{df} = n-1</math>.
<math>t = \frac {\bar{y}-\mu_0}{s_\bar{y}}</math>, where <math>\mu_0 </math> is the test value and <math>\text{df} = n-1</math>.