Casio 3.04 – o2)– tdf, – o2)+ tdf, Lower = (o1, Upper = (o1, C, df, sp2, sp2, sx22, sx12, sx12, sx12, (1–C)2, Lower = (o1, Upper = (o1

7-10-9

Confidence Intervals

When the two population standard deviations are equal (pooled)

Lower = (o1	– o2)– tn1+n2			sp2		1		+		1
		–2
			2							n2
						n1
Upper = (o1	– o2)+ tn1+n2			sp2	1		+		1
		–2
			2						n2
					n1

When the two population standard deviations are not equal (not pooled)

Lower = (o1

– o2)– tdf

sx12

+

sx22

2

n1

n2

Upper = (o1

– o2)+ tdf

sx12

+

sx22

2

n1

n2

df =

1

C2

+

(1–C)2

n –1

n

–1

1

2

sx12

C =

n1

sx12

+

sx22

n1

n2

Definition of Terms

C-Level :	confidence level (0 C-Level < 1)
List(1) :	list where sample 1 data is located
List(2) :	list where sample 2 data is located
Freq(1) :	frequency of sample 1 (1 or list name)
Freq(2) :	frequency of sample 2 (1 or list name)
Pooled :	On or Off
M1 :	sample mean of sample 1 data
sx1:	sample standard deviation of sample 1 (sx1 0)
n1 :	size of sample 1 (positive integer)
M2 :	sample mean of sample 2 data
sx2 :	sample standard deviation of sample 2 (sx2 0)
n2 :	size of sample 2 (positive integer)

Calculation Result Output

Lower : interval lower limit (left edge)

Upper : interval upper limit (right edge)

df : degrees of freedom

M1 : sample mean of sample 1 data

M2 : sample mean of sample 2 data

sx1 : sample standard deviation of sample 1

sx2 : sample standard deviation of sample 2

sp : pooled sample standard deviation (Displayed only when pooling is turned on.)

n1 : size of sample 1

n2 : size of sample 2

20090601