Suppose we did not have the EIB and eNO data as in DB14, but found a 5-minute difference standard deviation of 7 ppb for both normals and asthmatics. We want to test for a difference in means between these two groups using α 5 0.05 and power 5 0.80, where we take the clinically relevant difference to be 5 ppb. Assuming equal numbers of normals and asthmatics, what minimum sample size do we require?