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Confidence Intervals

Confidence Interval Command List

kZ Confidence Interval

1-Sample Z Interval

Command: OneSampleZInt￿

Description: This command obtains the confidence interval for the population mean when the population standard deviation is known.

The confidence interval is obtained using the following expressions.

Left = o – Z

 

α

 

σ

 

 

 

 

 

 

 

 

 

 

 

 

 

2

 

 

 

 

 

 

 

 

 

 

 

 

n

Right = o + Z

 

α

 

 

 

σ

 

 

 

 

 

 

 

 

 

 

 

2

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

n

α is the significance level, and 100 (1 – α)% is the confidence level. When the confidence level is 95%, for example, you would input 0.95, which produces α = 1 – 0.95 = 0.05.

Command Syntax

Syntax 1 (list format)

C-Level value, σ value, List, Freq (or 1)

* “Freq” can be omitted. Doing so sets “1” for “Freq”.

Syntax 2 (parameter format)

C-Level value, σ value, o value, n value

Definition of Terms

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

σ: population standard deviation (σ > 0)

List : list where sample data is located

Freq : frequency of sample (1 or list name)

o : mean of sample data

n : sample size (positive integer)

Input Example:

Syntax 1 (list format)

OneSampleZInt 0.95,1,list1,1

Syntax 2 (parameter format)

OneSampleZInt 0.95,1,64.3,20

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