Operation Manual

Appendix B: Reference Information 381
2-SampTTest
The following is the definition for the 2-SampTTest. The two-sample t statistic with degrees of freedom
df is:
where the computation of S and df are dependent on whether the variances are pooled. If the variances
are not pooled:
otherwise:
and Sxp is the pooled variance.
Financial Formulas
This section contains financial formulas for computing time value of money, amortization, cash flow,
interest-rate conversions, and days between dates.
Time Value of Money
where: PMT = 0
where:
PMT
y
x
C/Y
P/Y
I%
ƒ
=
=
=
=
=
0
C/Y  P/Y
(.01  I%)  C/Y
compounding periods per year
payment periods per year
interest rate per year
t
x
1
x
2
–
S
----------------
=
S
Sx
1
2
n
1
----------
Sx
2
2
n
2
----------
+=
df
Sx
1
2
n
1
----------
Sx
2
2
n
2
----------
+



2
1
n
1
1–
--------------
Sx
1
2
n
1
----------



2
1
n
2
1–
--------------
Sx
2
2
n
2
----------



2
+
-------------------------------------------------------------------------
=
Sx
p
n
1
1–Sx
1
2
n
2
1–Sx
2
2
+
df
------------------------------------------------------------------
=
S
1
n
1
-----
1
n
2
-----
Sx
p
+=
df n
1
n
2
2–+=
ie
yx1+ln
1–=
i
–
FV PV
1 N
1–=