We want to design new placebo-controlled trial to determine 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 a standard deviation of 50. How many subjects should be enrolled to ensure 80% power to detect a difference of 15 liters per minute with a two-sided test and standard deviation is .05?