The incidence rate ratio (and 95% confidence interval) of recovery for the remdesivir group compared to the placebo group is 1.29 (1.12, 1.49).Suppose you wish to present the findings from the study, but make the reference group the remdesivir cohort.What is the estimated IRR ratio and 95% CI for theplacebo cohort compared to the remdesivir cohort?

a. -1.29 (-1.49, -1.12)

b. 0.78 (0.67, 0.90)

c. 0.78 (1.22, 1.82)

d. This cannot be answered without knowing the number of persons who recovered in the remdesivir and placebo cohorts.