Casio fx-9860G AU PLUS, User Manual, Page: 344 / 590

20050401
o
.................................. mean of sample
x
σ
n -1
............................. sample standard deviation (
x
σ
n -1
>
0)
n .................................. size of sample (positive integer)
After setting all the parameters, use c to move the highlighting to “Execute” and then press
the function key shown below to perform the calculation.
•
1
(CALC) ... Performs the calculation.
Calculation Result Output Example
Left .............................. confidence interval lower limit (left edge)
Right ............................ confidence interval upper limit (right edge)
o
.................................. mean of sample
x
σ
n -1
............................. sample standard deviation
n
.................................. size of sample
u u u u u 2-Sample t Interval
2-Sample
t
Interval calculates the confidence interval for the difference between two
population means when both population standard deviations are unknown. The
t
interval is
applied to
t
distribution.
The following confidence interval applies when pooling is in effect.
α
is the level of significance.
The value 100 (1 –
α
) % is the confidence level.
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
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
6-6-9
Confidence Interval