Difference between r1.8 and the current

$ q = \displaystyle \frac {\overline{X_i}-\overline{X_j}}{\text{se}} $

$ se = \displaystyle \sqrt{ \frac {MS_{error}}{n} } $

cf.

$ t = \displaystyle \frac {\text{the difference between any two means}}{\text{the standard error of the difference between the two means}} $