TABLE 2-7c Illustrative, Approximate 90 Percent Confidence Intervals (CIs) Around 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% CI

ACS 3-Year Period Estimate 90% CI

ACS 5-YearPeriod Estimate 90% CI

2000 Long-Form Sample Estimate 90% CI

Total (20%of pop. total)

Poor (15% of ages 5–17)

2,500,000

500,000

75,000

14.1–15.9%

14.5–15.5%

14.6–15.4%

14.7–15.3%

1,000,000

200,000

30,000

13.5–16.5

14.1–15.9

14.3–15.7

14.6–15.4

500,000

100,000

15,000

12.9–17.1

13.8–16.2

14.1–15.9

14.4–15.6

250,000

50,000

7,500

12.0–18.0

13.3–16.7

13.7–16.3

14.1–15.9

100,000

20,000

3,000

10.3–19.7

12.3–17.7

12.9–17.1

13.6–16.4

65,000

13,000

1,950

9.1–20.9

11.6–18.4

12.4–17.6

13.3–16.7

50,000

10,000

1,500

8.3–21.7

11.2–18.8

12.0–18.0

13.0–17.0

25,000

5,000

750

5.5–24.5

9.6–20.4

10.8–19.2

12.2–17.8

20,000

4,000

600

4.4–25.6

8.9–21.1

10.3–19.7

11.9–18.1

10,000

2,000

300

0.1–29.9

6.4–23.6

8.3–21.7

10.6–19.4

5,000

1,000

150

(0.0–36.1)

2.8–27.2

5.6–24.4

8.8–21.2

3,000

600

90

(0.0–38.6)

1.4–28.6

4.4–25.6

8.0–22.0

1,500

300

45

(0.0–33.0)

4.6–25.4

7.0–23.0

9.7–20.3

500

100

15

(0.0–39.8)

0.7–29.3

3.9–26.1

5.8–24.2

NOTES: The 90 percent confidence interval (CI) ranges from an estimate minus the 90 percent margin of error to the estimate plus the 90 percent margin of error (see Table 2-7b). The 90 percent confidence intervals in parentheses are inexact. The lower limit of the confidence interval calculated in the standard way is a negative number, which is not possible. For simplicity, the lower limit has been set to 0 in these cases. See also the notes for Table 2-7b.



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