Casio ALGEBRA FX 2.0 PLUS - Manual (Page 43)

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o .................................. mean of sample
x σ
n -1
............................. sample standard deviation ( x σ
n -1
> 0)
n .................................. size of sample (positive integer)
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
Left .............................. interval lower limit (left edge)
Right ............................ interval upper limit (right edge)
o .................................. mean of sample
x σ
n -1
............................. sample standard deviation
n .................................. size of sample
u uu u u 2-Sample t Interval
2-Sample t 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. The value 100 (1 –
α
) % is
the confidence level.
Left = ( o
1
– o
2
)– t
α
2
Right = ( o
1
– o
2
)+ t
α
2
n
1
+n
2
–2 n
1
1 +
n
2
1
x
p n –1
2
σ
n
1
+n
2
–2 n
1
1 +
n
2
1
x
p n –1
2
σ
x
p n –1
=
σ
n
1
+ n
2
– 2
(n
1
–1)x
1 n –1
2 +(n
2
–1) x
2 n –1
2
σ σ
1-3-9
Confidence Interval (INTR)
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