37
27 Confidence Intervals
For a random sample of size from normal distribution with known variance , the
confidence intervals for the population mean may be calculated as given by:
(90% confidence interval)
(95% confidence interval)
(99% confidence interval)
: sample mean
Program
?→ A: -1.96×√(A ÷ )→ B: +1.96×√(A ÷ )→ C:B C
< 39 STEP >
:
:
INPUT A: Population variance
OUTPUT B,C: 95% confidence interval
Execution Example:
Calculate 95% confidence intervals.
Data: 1.4, 1.5, 1.3, 1.4, 1.7, 1.5, 1.3 Population variance
The interval of 95% certainty for is:
1.338< <1.548
n
σ
2
µ
x 1.64
σ
n
-------
×–
µ
x 1.64
σ
n
-------
×+<<
x 1.96
σ
n
-------
×–
µ
x 1.96
σ
n
-------
×+<<
x 2.57
σ
n
-------
×–
µ
x 2.57
σ
n
-------
×+<<
x
ON
MODE MODE MODE
1
PRGM
MODE MODE
1
SD
1
P1
x nx n
x
SHIFT
2
S-VAR
1
x
n
SHIFT
1
S-SUM
3
n
σ
2
B
µ
C<<
σ
2
0.02=
µ
µ
MODE MODE
1
SD
SD
S A
D R
P1
P2 P3 P4
G
1 4
M+
DT
SD
S A
D R
P1
P2 P3 P4
G
関数電卓事例集 .book 37 ページ 2002年9月2日 月曜日 午後6時51分