6-6-9

 

Confidence Interval

o ..................................

mean of sample

xσn-1 .............................

sample standard deviation (xσn-1>0)

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

size of sample (positive integer)

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)

o ..................................

mean of sample

xσn-1 .............................

sample standard deviation

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

size of sample

u 2-Sample t Interval

2-Samplet Interval calculates the confidence interval for the difference between two population means when both population standard deviations are unknown. The t interval is applied to t distribution.

The following confidence interval applies when pooling is in effect. α is the level of significance. The value 100 (1 – α) % is the confidence level.

 

 

α

1

 

 

1

 

Left = (o1 – o2)– tn1+n2 –2

 

 

 

 

xp σn–12

 

 

 

 

+

 

 

 

2

 

 

n

1

n

2

 

 

 

 

 

 

 

 

 

 

 

 

Right = (o1 – o2)+ tn1+n2 –2

 

α

xp σn–12

 

1

+

1

 

2

 

n1

n2

 

 

 

 

 

 

 

 

 

 

xpσn–1 =

(n1–1)x1σn–12

+(n2–1)x2σn–12

 

 

 

 

 

 

n1 + n2 – 2

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

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