t = [(F-1)*Sqrt(n-2)]/[(2*Sqrt(F(1-r squared)))].

HTH,

df for this t is n-2.
F = largest variance divided by the smallest variance
r = correlation between the matched or pair scors.
Check t for sign. If it is not significant than you can safely conclude
that you have met the equal variances assumption for the dependent t
-test.