TABLE 2.

Minimum and Maximum Length for 95% Clopper Pearson Exact CI for a Single Proportion

Sample size (n)	Minimum	Maximum
10	0.44	0.63
20	0.30	0.46
30	0.24	0.37
40	0.21	0.32
50	0.18	0.29
60	0.17	0.26
70	0.15	0.24
80	0.14	0.23
90	0.13	0.21

Note: The minimum and maximum values for the CI width were computed for proportions ranging from 0.1 to 0.9 by 0.1. The maximum width of a CI for a single proportion can be as large as 0.37 for a sample size of 30. For a given sample size, the 95% CI is widest for a proportion of 0.5 and narrowest when proportions are further away from 0.5. For example, when the proportion is 0.5, the maximum is 0.37 for n of 30; the minimum length is 0.24 when the proportion is 0.10 or 0.90.