TABLE 2-7b Illustrative, Approximate 90 Percent Margins of Error (MOEs), Plus or Minus an Estimate of 15 Percent Poor School-Age Children from the ACS and the 2000 Census Long-Form Sample, by Population Size of Area

Population Size of Area

Children Ages 5–17

ACS 1-Year Period Estimate 90% MOE

ACS 3-Year Period Estimate 90% MOE

ACS 5-Year Period Estimate 90% MOE

2000 Long-Form Sample Estimate 90% MOE

Total (20%of total pop.)

Poor (15% of ages 5–17)

2,500,000

500,000

75,000

±0.9%

±0.5%

±0.4%

±0.3%

1,000,000

200,000

30,000

±1.5

±0.9

±0.7

±0.4

500,000

100,000

15,000

±2.1

±1.2

±0.9

±0.6

250,000

50,000

7,500

±3.0

±1.7

±1.3

±0.9

100,000

20,000

3,000

±4.7

±2.7

±2.1

±1.4

65,000

13,000

1,950

±5.9

±3.4

±2.6

±1.7

50,000

10,000

1,500

±6.7

±3.8

±3.0

±2.0

25,000

5,000

750

±9.5

±5.4

±4.2

±2.8

20,000

4,000

600

±10.6

±6.1

±4.7

±3.1

10,000

2,000

300

±14.9

±8.6

±6.7

±4.4

5,000

1,000

150

(±21.1)

±12.2

±9.4

±6.2

3,000

600

90

(±23.6)

±13.6

±10.6

±7.0

1,500

300

45

(±18.0)

±10.4

±8.0

±5.3

500

100

15

(±24.8)

±14.3

±11.1

±9.2

NOTES: The 90 percent margin of error (MOE) is plus or minus (±) the standard error of an estimate times 1.65 (see Table 2-7a notes). The MOEs these cases, the subtraction of the MOE from the 15 percent estimate yields a negative value, which is an impossible result. Although the standard procedure for deriving the MOE is applied throughout the table, the underlying assumption of that procedure—that the sampling distribution of the estimate is approximately the normal distribution—is not applicable in these cases.



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