chapter 기초 통계 개념 - · pdf file1.1 왜 통계학인가? •1 1.1 왜...
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11.1?
1.1?
, , , , .
, , ,
.
.
.
1.
2.
3.
4. 3
5.
6.
7.
8.
9. 18
10.
(variability) .
, 3
. ,
.
.
1.1-1
1Chapter
01.indd 1 16. 4. 11. 10:51
2 1
1-1 32 1 . (1.5
) ,
, 5 . 1.1-1
.
3
, .
,
? (
) . 1 ( )
.
.
.
1.2
1.1-1 (population)
( ) ()
.
.
(population units) .
1-1
32
Freq
uenc
y42 44 46 48 50
01
23
45
67
1 MPa( ) , 15 cm, 30 cm , / 0.4, 28
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31.2
(a) 1.1-1, 1
.
(b) 1.1-1, 3 ,
. .
(c) 1.1-1, 5 .
.
(d) 1.1-1, 8 , .
.
1.2-1 (c) ,
. 1.1-1 2
.
. (inherent variability) (intrinsic variability)
. ()
(census) . , .
.
.
(a) ,
18 .
(b) ,
.
,
, .
(a) ( 1.1-1, 4 7)
.
.
(b) ( 1.1-1, 6),
.
.
1.2-1
1.2-2
1.2-3
01.indd 3 16. 4. 11. 10:51
4 1
(
),
.
() . 18
.
.
.
(a) (sample proportion)(
) (population proportion) . ( .) (
1.6.1 .)
(b) () () . (
.) ( 1.6.2
.)
(c)
. ( .)
.
1-2 50 x .
10 .2
50 ,
.3
, .
.
. 20
20
( ). (1.6.2 )
(sampling variability)
.
1.2-4
1.2-5
2 1.3 .3 6 .
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51.2
1.2-5 50 10
. 1-3
.
. .
. 1.1-1
. 1.1
. 1.6.2 .
(population parameter) .
1.2-6
1-2
()
()
20 25 30 35 40 45 50 55
100
200
300
400
Chest girthW
eigh
t
1-3
10
Chest girth
Wei
ght
20 25 30 35 40 45 50 55
100
200
300
400
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6 1
1.2-4 .
1.6 1.7 .
. (statistics)
. ,
1.6 1.7 , .
.
.
.
.
. (statistical
inference)
.
.
.
.
. .
( )
.
,
,
.
(estimation)[(point) (interval)
] , (hypotheses) (testing).
( 1.1-1, 1).
(
1.1-1, 7). (prediction) .
( 1.1-1, 5).
.
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71.3
1.
.
(a) .
(b) ?
2.
.
10
.
(a) .
(b) ?
(c) () .
3. 1 2 .
2/3 .
2
.
(a) .
(b) () ?
(c) ?
4.
?
175
.
(a) .
(b) .
(c) ?
5.
, (section)
.
.
.
(a) ?
(b) .
(c) () ?
(d) () ?
1.3
1.3.1
,
(representative) .
.
(
) 1936 Literary Digest . Literary Digest
. 1936
, 32
. 1.3.4
. 230 ( )
01.indd 7 16. 4. 11. 10:51
8 1
Literary Digest . 5
.
. ,
.
. .
1.3.2
(simple random sampling).
n , n
.
.
N n
1 N (random number generator)
n n .
1 N ,
.
1 N n (
).
Sixty KitchenAid .
12 .
(a) 60 12 .
(b) (a) R .
1 60 . 1
60 60 . 12
. 12 60 n 5 12
. R .
:R
(1.3.1)
y 5 , sample(seq(1, 60), size 5 12) R 12
1.3-1
01.indd 8 16. 4. 11. 10:51
91.3
. y y 12
. 12 6, 8, 57, 53, 31, 35, 2, 4, 16, 7, 49,
41.
(infinite) .
.
.
.
. .
50 50 100 10
. (a) 1 50
5 . (b) . 10
?
( )
. .
4 6 ,
. , 10
. .
1.3-2 (stratified sampling) .
(strata),
. , , ,
.
.
. (proportionate allocation)
1.3-2 . , .
(
) .
.
1.3-2
01.indd 9 16. 4. 11. 10:51
10 1
1.3.3
(with replacement) (without
replacement) .
.
{, }.
. .
N ()
( N 2 1
, N 2 2 ).
( ) .
(conceptual convenience) ,
.
. (,
) .
(bootstrap) .
.
1.3.4
.
. ,
. 80 %
.
.
.
,
. 2 3
1 4 .
1936 Literary Digest
. Literary Digest ,
. 1936
.
.
01.indd 10 16. 4. 11. 10:51
111.3
1,000 230 .
. Literary Digest
(
[1948 - ] Literary Digest ).
.
. .
,
.
.
1. 1.2 5
. (i)
. (ii)
.
?
2. 3
. 20% A ,
50% B , 30% C .
(QCT) 100
.
QCT A 20, B 50, C
30 QC
.
(a) 100
?
(b) (a) .
,
?
3.
.
,
.
(a) ?
(b)
?
(c)
?
(d)
(overestimate) (underestimate)
?
4. 2007 1 9
.
70 15
. 70 15
. R 15
. R
.
5. 90
.
5 . 90
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12 1
5 .
R .
6.
.
12 1,000
, 100
.
(a) 1,000 100
.
(b) 1,000 800 , 150
, 50 .
100
.
(c) (a) (b) R
.
7.
. 3
.
.
8. A B, . B
70% .
1 50
.
A
, B
.
? .
9. 2 .
2/3 .
.
6
, 3
. 9
? .
1.4
1.1
(quantitative). , (qualitative)
(categorical) .
(strength) (ordinal).
. 21
, 11 .
(variable) .
(discrete) . .
. , , ,
(continuous) .
, ,
(univariate), (bivariate) (multivariate)
.
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131.4
(a) (
) , .
(b) 18 .
.
,
.
(c)
. ,
, .
.
.
X . X X
(random variable) .
X .
(underlying population) .
. 1.1-1 3 .
.
. (statistical population) .
( ) , (
) .
18 .
0 10 ,
. 0 0 , 1
1 .
.
.
1.4-1
1.4-2
01.indd 13 16. 4. 11. 10:51
14 1
()
.
. ,
( 1.6 ).
1. 500 0, 1, 2
N0 5 190, N1 5 160, N2 5 150
.
(a) ?
(b) , ?
(c) , , ?
2. /
.
(a)
. :
(b) . :
(c) . :
(d) . :
.
.
3. BMW
. N
n n
.
(a) , , ?
(b) , ?