Casio ClassPad 300 PLUS, User Manual

Page: 373 / 753

20050501
2-Sample
t
Test
Command: TwoSampleTTest
䡺
Description: This command compares the population means of two populations when
population standard deviation is unknown. A 2-Sample
t Test is used for t
distribution.
t
=
o
1
–
o
2
x
1 n –1
2
σ
n
1
+
x
2 n –1
2
σ
n
2
o
1
: mean of sample 1 data
o
2
: mean of sample 2 data
x
1
σ
n -1
: standard deviation of sample 1
x
2
σ
n -1
: standard deviation of sample 2
n
1
: size of sample 1
n
2
: size of sample 2
This formula is applicable when the population standard deviations of the two
populations are not equal. The denominator is different when the population
standard deviations are equal.
The
t
distribution degrees of freedom
df
and
x
p
σ
n -1
differ according to whether
the population standard deviations of the two populations are equal.
When the two population standard deviations are equal (pooled)
df
=
n
1
+
n
2
– 2
x
p n –1
=
σ
n
1
+
n
2
– 2
(
n
1
–1)
x
1 n –1
2
+(
n
2
–1)
x
2 n –1
2
σ σ
When the two population standard deviations are not equal (not pooled)
df =
1
C
2
n
1
–1
+
(1–
C
)
2
n
2
–1
C =
x
1
n
–1
2
σ
n
1
+
x
2
n
–1
2
σ
n
2
x
1 n –1
2
σ
n
1
Command Syntax
Syntax 1 (list format)
“
µ
1
condition”, List(1), List(2), Freq(1) (or 1), Freq(2) (or 1), Pooled condition (On
or Off)
* “Freq” can be omitted. Doing so sets “1” for “Freq”.
* “Pooled” can be omitted. Doing so sets “Off” for “Pooled”.
Syntax 2 (parameter format)
“
µ
1
condition”,
o
1
value, x
1
σ
n -1
value, n
1
value,
o
2
value, x
2
σ
n -1
value, n
2
value,
Pooled condition (On or Off)
* “Pooled” can be omitted. Doing so sets “Off” for “Pooled”.
7-9-7
Tests