Table PTC3. Confidence interval for relative risk (ratio of two proportions)

See nQuery Advisor® manual Appendix for normal approximation formula. Figure PTC3 shows computations for two examples. Additional values checked against Table 11 in Lemeshow, S., Hosmer, D.W., Janella, K., and Lwanga, S.K. Adequacy of Sample Size in Health Studies John Wiley & Sons LTD (1990).

Figure PTC3. In the first and third columns, nQuery Advisor® 7.0 computed n, in the second and fourth columns, distance.