Casio SERIES FX-9860G - Manual (Page 347)

20070201
¯x ................................... 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 ............................... confi dence interval lower limit (left edge)
Right ............................. confi dence interval upper limit (right edge)
o ................................... mean of sample
x σ
n -1
............................. sample standard deviation
n .................................. size of sample
u 2-Sample t Interval
2-Sample t Interval calculates the confi dence 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 confi dence interval applies when pooling is in effect.
α is the level of
signifi cance. The value 100 (1 –
α
) % is the confi dence 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
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
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
Confi dence Interval