请教AA72的思路

AA72：

The following appeared as part of a recommendation from the business manager of a department store:  “Local clothing stores reported that their profits decreased, on average, for the three-month period between August 1 and October 31. Stores that sell products for the home reported that, on average, their profits increased during this same period. Clearly, consumers are choosing to buy products for their homes instead of clothing. To take advantage of this trend, we should reduce the size of our clothing departments and enlarge our home furnishings and household products departments.”

我就想出了一个“3个月的样本不具有代表性”，然后就想不出了- -

还望各位相助！