A randomized clinical trial investigates whether treatment with a nicotine patch in addition to varenicline produces higher rates of smoking abstinence than varenicline alone. Selecting the minimum detectible difference (MDD), also known as the minimum clinical significant difference, requires the expertise of the researcher. Some information about the baseline rate is usually available in the literature because this rate is often based on a therapy that has been studied. However, the minimum detectible difference choice is more subjective.

In this trial, approximately 200 patients per group (N=400 in total) are needed for a minimum detectable difference of 14%, 80% power, and alpha=0.05. The power curves are attached. Approximately, how many patients per group would you need for a slightly smaller minimum detectable difference of 12%? Assume that all other things are the same. Choose the closest available answer.