Tables and Reference Information A-53
8399APXA.DOC TI-83 international English Bob Fedorisko Revised: 02/19/01 1:25 PM Printed: 02/19/01 1:40 PM
Page 53 of 58
The following is the definition for the 2.SampTTest. The
two-sample t statistic with degrees of freedom df is:
txx
S
=−
12
where the computation of S and df are dependent on
whether the variances are pooled. If the variances are not
pooled:
SSx
n
Sx
n
=+
12
1
22
2
df
Sx
n
Sx
n
n
Sx
nn
Sx
n
=
+
−
+−
12
1
22
2
2
1
12
1
2
2
22
2
2
1
1
1
1
otherwise:
Sx nSxnSx
df
p=−+−() ()
11
222
2
11
Snn
Sxp
=+
11
12
df n n
=+−
12
2
and Sxp is the pooled variance.
2-SampTTest