1
SIMPLERANDOMSAMPLE
2
SYSTEMATICSAMPLE
3
CLUSTERSAMPLE
4
SECONDARYDATA
5
PROBABILITY
6
STRATIFIED
7
STATISTICS
8
TECHNIQUE
9
ACCURATE
10
UNBIAS
11
CENSUS
12
ERROR
13
BIAS
14
POLL
U
T
K
F
S
T
R
A
T
I
F
I
E
D
U
I
Y
F
A
F
U
D
I
G
B
R
E
A
C
C
U
R
A
T
E
P
X
A
I
A
R
O
S
Z
S
C
L
U
S
T
E
R
S
A
M
P
L
E
I
T
V
D
C
E
B
G
P
M
Y
E
R
R
O
R
K
Z
B
U
F
A
N
W
I
P
J
E
M
S
A
A
O
L
E
S
D
I
E
A
D
D
S
M
T
I
T
Y
A
D
I
I
E
A
K
Y
B
N
K
U
O
Y
A
F
S
L
W
B
S
K
D
C
Z
O
U
S
M
T
Q
Q
E
R
I
I
I
S
I
W
M
C
T
F
P
L
O
T
D
V
I
A
J
A
B
Q
T
W
Y
I
O
E
E
K
R
Q
C
E
O
A
F
A
N
D
N
F
A
O
R
O
D
I
U
O
O
A
Y
M
S
H
R
O
S
N
U
S
T
Q
X
Q
N
O
V
V
B
R
S
A
T
O
B
P
H
O
C
Y
S
C
R
T
A
S
M
Q
A
Y
E
T
T
E
P
X
F
C
U
O
U
F
E
E
R
A
S
Z
B
C
N
I
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L
O
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X
E
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U
I
M
A
C
E
I
M
W
I
E
E
C
A
X
A
Q
V
S
A
M
E
O
G
H
L
B
U
S
L
N
U
S
U
U
P
I
O
A
I
P
O
A
G
N
P
B
A
F
I
S
W
A
O
S
R
L
P
X
Y
Z
U
T
X
I
M
E
C
V
T
U
S
M
U
A
I
S
O
W
S
N
E
O
E
Q
I
E
J
U
Y
S
B
P
T
D
I
G
J
P
Z
P
R
S
K
U
S
P
O
L
L
I
T
L
Y
O
O
E
C
B
I
X
E
F
X
E
I
I
Z
X
U
R
O
E
O
C
A
G
E
V