20010101
u
uu
u
u
2-Sample
t
Test
2-Sample
t
Test
compares the population means when the population standard deviations
are unknown. The
2-Sample
t
Test
is applied to
t
-distribution.
The following applies when pooling is in effect.
t
=
o
1
–
o
2
n
1
1 +
n
2
1
x
p
n
–1
2
σ
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
df
=
n
1
+
n
2
– 2
The following applies when pooling is not in effect.
t
=
o
1
–
o
2
x
1
n
–1
2
σ
n
1
+
x
2
n
–1
2
σ
n
2
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
Perform the following key operations from the statistical data list.
3
(TEST)
c
(T)
c
(2-Smpl)
1-2-13
Tests (TEST)
o
1
: mean of sample 1
o
2
: mean of sample 2
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
x
p
σ
n
-1
: pooled sample standard
deviation
df
: degrees of freedom
o
1
: mean of sample 1
o
2
: mean of sample 2
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
df
: degrees of freedom
20011101