Casio CFX-9970G User Manual page 318

18 - 7
Confidence Interval
u u u u u 2-Prop Z Interval
2-Prop Z Interval calculates the confidence interval when the proportions of two
samples are known. The 2-Prop Z Interval is applied to standard normal distribu-
tion.
The following is the confidence interval.
Perform the following key operation from the statistical data list.
Data is specified using parameter specification. The following shows the meaning
of each item.
Example
x x
– Z )
1 2
Left = –
n n
2
1 2
x x
+ Z )
1 2
Right = –
n n
1 2
4(INTR)
1(Z)
4(2-P)
C-Level ........... confidence level (0 < C-Level < 1)
x
.................... sample 1 data value (
1
n
.................... sample 1 size (positive integer)
1
x
.................... sample 2 data value (
2
n
.................... sample 2 size (positive integer)
2
Execute .......... Executes a calculation
To calculate the 2-Prop Z Interval using parameter value
specification
For this example, we will obtain the 2-Prop Z Interval when
C-Level = 0.95,
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diwgcw
1(CALC)
Left ................. interval lower limit (left edge)
Right ............... interval upper limit (right edge)
x x x
1 1
1– n 2 1– n
n n
1 1 2
+
n n
1 2
x x
x
1
1 1– n 2 1– n
n n
1 1 2
+
n n
2
1
x
> 0)
1
x
> 0)
2
x n
= 49, = 61,
1 1
n n
, : sample size
1 2
x
2
x x
, : data
1 2
2
x
2
2
2
x n
= 38 and = 62.
2 2
298