Investigators were designing a randomized clinical trial to evaluate whether a new treatment reduces the risk of disease. They determined that their total sample size, where half of the participants are assigned to treatment and half are assigned to placebo, provides 80% power to detect a relative risk of 0.7, assuming a signicance level of 0.05. A reviewer suggested that the researchers should design their trial to detect a relative risk of 0.9. How should the investigators adjust their sample size to detect a relative risk of 0.9 (instead of 0.7) without changing other aspects of their study design? Should the investigators increase their sample size, decrease their sample size, or keep the sample size the same? Briey explain your