People can develop allergic reactions to sulfites, a family of chemical compounds often used for commercial food preservation. Researchers examined a sample of 21 patients with hypertension who had sought treatment regarding some allergic reaction. The published findings state that 9 of them were sensitive to sulfites. Why should we use the plus four method to compute a 95% confidence interval for the population proportion of sulfite sensitivity among patients with hypertension and an allergy?

Question

Quizplus · Accepted Answer

The plus four method is a correction for small sample sizes when computing confidence intervals for population proportions. When the sample size is small, using the large-sample method may not yield accurate results. In this case, the sample size is only 21, and the counts of successes (9) and failures (12) are also relatively small. Therefore, using the plus four method is more suitable for computing the confidence interval.

People Can Develop Allergic Reactions to Sulfites, a Family of Chemical