20060301
When the two population standard deviations are equal (pooled)
When the two population standard deviations are not equal (not pooled)
Definition of Terms
C-Level : confidence level (0
<
C-Level < 1)
List(1) : list where sample 1 data is located
List(2) : list where sample 2 data is located
Freq(1) : frequency of sample 1 (1 or list name)
Freq(2) : frequency of sample 2 (1 or list name)
Pooled : On or Off
o
1
: sample mean of sample 1 data
x
1
σ
n
−1
: sample standard deviation of sample 1 (
x
1
σ
n
−1
>
0)
n
1
: size of sample 1 (positive integer)
o
2
: sample mean of sample 2 data
x
2
σ
n
−1
: sample standard deviation of sample 2 (
x
2
σ
n
−1
>
0)
n
2
: size of sample 2 (positive integer)
Calculation Result Output
Left : interval lower limit (left edge)
Right : interval upper limit (right edge)
df
: degrees of freedom
o
1
: sample mean of sample 1 data
o
2
: sample mean of sample 2 data
x
1
σ
n
–1
: sample standard deviation of sample 1
x
2
σ
n
–1
: sample standard deviation of sample 2
x
p
σ
n
–1
: pooled sample standard deviation (Displayed only when pooling is
turned on.)
n
1
: size of sample 1
n
2
: size of sample 2
Left = (o
1
– o
2
)– t
α
2
Right = (o
1
– o
2
)+ t
α
2
n
1
+n
2
–2
n
1
1
+
n
2
1
x
p
n–1
2
σ
n
1
+n
2
–2
n
1
1
+
n
2
1
x
p
n–1
2
σ
Left = (o
1
– o
2
)– t
α
2
Right = (o
1
– o
2
)+ t
α
2
n
1
+n
2
–2
n
1
1
+
n
2
1
x
p
n–1
2
σ
n
1
+n
2
–2
n
1
1
+
n
2
1
x
p
n–1
2
σ
Left = (o
1
– o
2
)– t
df
α
2
Right = (o
1
– o
2
)+ t
df
α
2
+
n
1
x
1 n–1
2
σ
n
2
x
2 n–1
2
σ
+
n
1
x
1 n–1
2
σ
n
2
x
2 n–1
2
σ
Left = (o
1
– o
2
)– t
df
α
2
Right = (o
1
– o
2
)+ t
df
α
2
+
n
1
x
1 n–1
2
σ
n
2
x
2 n–1
2
σ
+
n
1
x
1 n–1
2
σ
n
2
x
2 n–1
2
σ
C =
df =
1
C
2
n
1
–1
+
(1–C)
2
n
2
–1
+
n
1
x
1 n–1
2
σ
n
1
x
1 n–1
2
σ
n
2
x
2 n–1
2
σ
C =
df =
1
C
2
n
1
–1
+
(1–C)
2
n
2
–1
+
n
1
x
1 n–1
2
σ
n
1
x
1 n–1
2
σ
n
2
x
2 n–1
2
σ
7-10-9
Confidence Intervals
20070301