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Confidence Intervals

kt Confidence Interval

1-Sample t Interval

Command: OneSampleTInt￿

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

The confidence interval is obtained using the following expressions.

The confidence level is 100 (1 – α)%.

Left = o– tn – 1

α xσn–1

2

 

 

 

 

 

 

 

 

 

 

 

 

 

n

 

 

 

Right = o+ tn – 1

α xσn–1

2

 

 

 

 

 

 

 

n

 

Command Syntax

Syntax 1 (list format)

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

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

Syntax 2 (parameter format)

C-Level value, o value, xσn-1value, n value

Definition of Terms

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

List : list where sample data is located

Freq : frequency of sample (1 or list name)

o : mean of sample data

xσn-1 : sample standard deviation (xσn-1>0)

n : sample size (positive integer)

Input Example:

Syntax 1 (list format)

OneSampleTInt 0.95,list1,1

Syntax 2 (parameter format)

OneSampleTInt 0.95,66.3,8.4,12

Calculation Result Output

Left : interval lower limit (left edge)

Right : interval upper limit (right edge)

o : mean of sample data

xσ n–1 : sample standard deviation

n : sample size

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