TI-83 Plus Tables and Reference Information 726
2.SampTTest
The following is the definition for the 2.SampTTest. The two-sample t
statistic with degrees of freedom df is:
S
xx
t21−
=
where the computation of S and df are dependent on whether the
variances are pooled. If the variances are not pooled:
2
2
2
1
2
1n
Sx
n
Sx
S+=
2
2
2
2
2
2
1
2
1
1
2
2
2
2
1
2
1
1
1
1
1
−
+
−
+
=
n
Sx
nn
Sx
n
n
Sx
n
Sx
df