single sample t-test formula 

-OR-

where

Df = n – 1

Confidence Interval

independent measures t-test formulas (equal sample sizes only)

-OR-

where

df = n1 + n2 – 2

-for pooled variances (equal or unequal sample sizes or n’s)

ANOVA (analysis of variance) formulas

df(tot) = N -1

df(between) = K – 1

df(within) = N – K