1-3-7

Confidence Interval (INTR)

u 2-Prop Z Interval

2-PropZ Interval uses the number of data items to calculate the confidence interval for the defference between the proportion of successes in two populations.

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

Left = x1 – x2 – Z α

n1 n2 2

Right = x1 – x2 + Z α

n1 n2 2

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

n1, n2

: size of sample

 

x1

 

x1

 

 

 

x2

 

 

x2

 

 

 

 

 

 

 

 

 

 

n1

1–

n1

 

+

 

n2

1–

n2

 

 

x1, x2

: data

 

 

 

n1

 

 

 

n2

 

 

 

 

 

 

 

 

 

 

 

 

 

 

x1

 

x1

 

 

x2

 

x2

 

 

 

 

n1

1– n1

+

n2

1– n2

 

 

 

 

 

 

n1

 

 

 

 

n2

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Perform the following key operations from the statistical data list.

4(INTR)

b(Z)

e(2-Prop)

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

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

confidence level (0 <C-Level < 1)

x1 .................................

data value (x1 >0) of sample 1

n1 .................................

size (positive integer) of sample 1

x2 .................................

data value (x2 >0) of sample 2

n2 .................................

size (positive integer) of sample 2

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

list for storage of calculation results (None or List 1 to 20)

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

executes a calculation

After setting all the parameters, align the cursor with [Execute] and then press the function key shown below to perform the calculation.

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

Calculation Result Output Example

20011101