6-6-6

Confidence Interval

u 1-Prop Z Interval

1-PropZ Interval uses the number of data to calculate the confidence interval for an unknown proportion of successes.

The following is the confidence interval. α is the level of significance. The value 100 (1 – α) % is the confidence level.

 

 

 

 

 

 

 

α

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

n : size of sample

 

x

 

 

 

1

 

x

 

x

Left =

 

 

 

– Z

 

 

 

 

 

 

 

 

 

 

 

 

1–

 

 

 

 

x : data

n

 

 

2

 

 

 

n

n

n

 

 

 

 

 

 

 

 

α

 

 

 

 

 

 

 

 

 

 

Right =

x

 

+ Z

 

 

 

1 x

1–

x

 

n

 

 

 

2

 

 

 

n

 

n

n

 

 

Perform the following key operations from the statistical data list.

4(INTR)

1(Z)

3(1-P)

Data is specified using parameter specification. The following shows the meaning of each item.

C-Level ........................

confidence level (0 <C-Level < 1)

x ..................................

data (0 or positive integer)

n ..................................

size of sample (positive integer)

Save Res ....................

list for storage of calculation results (None or List 1 to 26)

Execute .......................

executes a calculation

After setting all the parameters, use c to move the highlighting to “Execute” and then press the function key shown below to perform the calculation.

• 1(CALC) ... Performs the calculation.

Calculation Result Output Example

Left ..............................

confidence interval lower limit (left edge)

Right ............................

confidence interval upper limit (right edge)

ˆp ..................................

estimated sample proportion

n ..................................

size of sample

20050401