Confidence Interval for Binomial Proportions
Newcombe (1998) suggests using alternatives to the usual Wald procedure to obtain confidence intervals for a proportion, particularly for proportions less than 0.2 or greater than 0.8. He suggests the exact binomial method and Wilson’s (1927) method provide slightly better coverage. Confidence intervals for both Wald and Wilson methods may be computed by using [attachment:BinomialCIs_wald_re.xls this spreadsheet].
References
Newcombe RG. (1998) Two sided confidence intervals for the single proportion: Comparison of seven methods. Statistics in Medicine 1998;17:857-872
Wilson EB (1927) Probable inference, the law of succession, and statistical inference. J Am Stat Assoc 22, 209-212.
Last updated on 18 October, 2006