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Table 1 Values (in %) of relative standard errors obtained from the four strategies adopted in estimating remote sensing-based forest cover for the three artificial populations P1, P2 and P3 and each combination of n and m. Values in brackets represent the approximate expectations of the standard error estimators adopted with OPSS

From: Sampling strategies for estimating forest cover from remote sensing-based two-stage inventories

Population

nxm

N

m

SRSWOR  +  HT

OPSS  +  HT

SRSWOR  +  D

OPSS  +  D

P1

100

4

25

25.0

22.1 (23.2)

14.2

10.3 (10.3)

\( \overline{Y}=0.62 \)

10

10

18.2

14.4 (15.3)

12.9

7.8 (8.1)

R 2 = 0.80

25

4

14.2

9.2 (10.8)

11.7

6.6 (7.3)

400

16

25

12.3

9.8 (11.5)

7.1

4.7 (5.3)

20

20

11.1

8.9 (10.7)

6.5

4.8 (5.7)

25

16

10.0

8.0 (9.9)

5.9

4.7 (5.7)

2000

40

50

7.1

5.2 (7.0)

3.4

2.2 (3.2)

50

40

6.3

4.4 (6.6)

3.2

2.4 (3.5)

100

20

4.5

2.9 (5.0)

2.8

1.9 (3.5)

P2

100

4

25

28.7

25.9 (27.1)

13.4

8.7 (8.7)

\( \overline{Y}=0.59 \)

10

10

20.4

16.7 (17.7)

12.8

7.1 (7.4)

R 2 = 0.92

25

4

15.4

10.2 (12.2)

11.8

6.4 (7.0)

400

16

25

14.2

11.4 (13.5)

11.8

4.2 (4.7)

20

20

12.7

10.3 (12.4)

6.2

4.5 (5.3)

25

16

11.4

9.1 (11.4)

5.7

4.5 (5.5)

2000

40

50

8.3

5.8 (8.2)

3.0

1.9 (2.7)

50

40

7.3

5.1 (7.6)

2.8

2.2 (3.3)

100

20

5.2

3.4 (5.7)

2.7

1.8 (3.4)

P3

100

4

25

33.0

30.1 (31.6)

11.8

5.2 (5.1)

\( \overline{Y}=0.57 \)

10

10

22.9

19.1 (20.2)

12.2

5.3 (5.6)

R 2 = 0.99

25

4

16.7

11.0 (13.4)

11.6

5.3 (5.8)

400

16

25

16.3

13.2 (15.6)

5.9

2.6 (3.0)

20

20

14.6

11.9 (14.3)

5.6

3.5 (4.3)

25

16

13.1

10.4 (13.0)

5.2

3.8 (4.8)

2000

40

50

9.6

6.5 (9.5)

2.3

1.1 (1.6)

50

40

8.5

5.8 (8.6)

2.3

1.6 (2.7)

100

20

5.9

3.8 (6.3)

2.5

1.5 (3.1)