User Manual

20050501
2-Prop Z Interval
Command: TwoPropZInt 䡺
Description: This command obtains the confidence interval of the difference between the
proportions of successes of two populations.
The confidence interval is obtained using the following expressions.
The confidence level is 100 (1 – α )%.
Left = – – Z
α
2
x
1
n
1
x
2
n
2
n
1
n
1
x
1
1–
n
1
x
1
+
n
2
n
2
x
2
1–
n
2
x
2
Right = – + Z
α
2
x
1
n
1
x
2
n
2
n
1
n
1
x
1
1–
n
1
x
1
+
n
2
n
2
x
2
1–
n
2
x
2
n1, n2 : sample size
x1, x2 : data
Command Syntax
C-Level value, x1 value, n1 value, x2 value, n2 value
Definition of Terms
C-Level: confidence level (0 < C-Level < 1)
x1 : data value (integer, x1 > 0) of sample 1
n1 : size of sample 1 (positive integer)
x2 : data value (integer, x2 > 0) of sample 2
n2 : size of sample 2 (positive integer)
Input Example:
TwoPropZInt 0.95,132,200,90,150
Calculation Result Output
Left : interval lower limit (left edge)
Right : interval upper limit (right edge)
ˆp 1 : estimated proportion of sample 1
ˆp 2 : estimated proportion of sample 2
n1 : size of sample 1
n2 : size of sample 2
7-10-5
Confidence Intervals