Suppose we want to design a new placebo controlled trial to elevate an experimental medication to in

Suppose we want to design a new placebo controlled trial to elevate an experimental medication to increase lung capacity. The primary outcome is peak expiratory flow rate , a continuous variable measured in liters per minute . The primary outcome will be measured after 6 months on treatment. The investigators expect to lose 10% of the participants over the course of follow up. The mean peak expiratory flow rate in adults is 300 with a standard deviation of 50. How many subjects should de enrolled to ensure 80% power to detect a difference of 15 liters per minute with a two sided test and []=0.05?