(17KB)| Table A-4. | Sampling errors (95 percent confidence level) for percentages estimated from the Gallup Poll: 1992, 1993, and 1996 to 2004 |
| Size of sample
Percent |________________________________________________
| 1,500| 1,000| 750 | 600 | 400 | 200 | 100
_____________________________|______|______|______|______|______|______|______
Recommended allowance for | | | | | | |
sampling error of a | | | | | | |
percentage | | | | | | |
Percentages near 10 or 90 .| 2| 2| 3| 3| 4| 5| 8
Percentages near 20 or 80 .| 3| 3| 4| 4| 5| 7| 10
Percentages near 30 or 70 .| 3| 4| 4| 5| 6| 8| 12
Percentages near 40 or 60 .| 3| 4| 5| 5| 6| 9| 12
Percentages near 50 .......| 3| 4| 5| 5| 6| 9| 13
_____________________________|______|______|______|______|______|______|______ |
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SOURCE: Phi Delta Kappa, Phi Delta Kappan, "The Annual Gallup Poll of the Public's Attitudes Toward the Public Schools," 1992, 1993, and 1996 to 2004. |