Casio FX-9750G PLUS User's Manual & Technical Reference page 324

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Confidence Interval
u u u u u 2-Sample Z Interval
2-Sample Z Interval calculates the confidence interval for the difference between
two population means when the population standard deviations of two samples
are known.
The following is the confidence interval. The value 100 (1 –
level.
Perform the following key operations from the statistical data list.
The following shows the meaning of each item in the case of list data specifica-
tion.
296
Example To calculate the 1-Sample
For this example, we will obtain the
{11.2, 10.9, 12.5, 11.3, 11.7}, when C-Level = 0.95 (95% confi-
dence level) and σ = 3.
1(List)c
a.jfw
dw
1(List1)c1(1)c1(CALC)
Left ................. interval lower limit (left edge)
Right ............... interval upper limit (right edge)
o ..................... sample mean
x σ
................ sample standard deviation
n -1
n
..................... sample size
) – Z α
Left = (o – o
1 2
) + Z α
Right = (o – o
1 2
4(INTR)
1(Z)
2(2-S)
Data ................ data type
C-Level ........... confidence level (0 < C-Level < 1)
Z
Interval for one list of data
σ σ
2 2
+
1 2
n n
2
1 2
σ σ
2 2
+
1 2
n n
2
1 2
Z
Interval for the data
α
) % is the confidence
: sample 1 mean
o
1
: sample 2 mean
o
2
σ
: population standard deviation
1
of sample 1
σ
: population standard deviation
2
of sample 2
n
: sample 1 size
1
n
: sample 2 size
2