We want to design new placebo-controlled trial to measure an experimental medication to increaselung capacity. The primary outcome is peak expiratory flow rate, a continuous varialb emeasured in leters per minute. The primary outcome will be measured after six months on treatment. The expected peak expiratory flow rate in adults is 300 with standard deviation of 50. How many subjects must be enrolled to ensure 80% power to detect a difference of 15 liters per minute with two-sided test and standard deviation is .05?