7-10-5

Confidence Intervals

Input Example:

Syntax 1 (list format)

TwoSampleZInt 0.95,15.5,13.5,list1,list2,1,1

Syntax 2 (parameter format)

TwoSampleZInt 0.95,1,1.5,418,40,402,50

1-Prop Z Interval

Menu: [Interval]-[One-Prop ZInt]

Description: This command obtains the confidence interval of the proportion of successes in a population.

The confidence interval is obtained using the following expressions.

The confidence level is 100 (1 – α)%.

Left =

x

– Z

α

1 x

x

n: sample size

n

2

n n 1– n

x: data

Right =

x

+ Z

α

1 x

 

x

n

2

n n

1– n

Definition of Terms

C-Level: confidence level (0 <C-Level < 1)

x : data (0 or positive integer)

n : sample size (positive integer)

Calculation Result Output

Left : interval lower limit (left edge)

Right : interval upper limit (right edge)

ˆp : estimated sample proportion

n : sample size

Example

Data : 2048

Sample size : 4040

Significance level : 1% ( = confidence level : 99%)

•Statistics Wizard Operation

(1)On the menu bar, tap [Calc] and then [Interval].

(2)Select [One-Prop ZInt] and then tap [Next >>].

(3)Input values.

(4)Tap [Next >>].

20060301