Casio fx-9860G AU - Page 323

20050401
uu
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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 = n1 + n2 – 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)
2(t)
2(2-S)
6-5-13
Tests
o1 :mean of sample 1
o2 :mean of sample 2
x1 σ n-1 : standard deviation of
sample 1
x2 σ n-1 : standard deviation of
sample 2
n1 : size of sample 1
n2 : size of sample 2
xp σ n-1 : pooled sample standard
deviation
df : degrees of freedom
o1 :mean of sample 1
o2 :mean of sample 2
x1 σ n-1 : standard deviation of
sample 1
x2 σ n-1 : standard deviation of
sample 2
n1 : size of sample 1
n2 : size of sample 2
df : degrees of freedom