The following appeared as part of an article in a business magazine.

"A recent study rating 300 male and female advertising executives according to the average number of hours they sleep per night showed an association between the amount of sleep the executives need and the success of their firms. Of the advertising firms studied, those whose executives reported needing no more than six hours of sleep per night had higher profit margins and faster growth. On the basis of this study, we recommend that businesses hire only people who need less than six hours of sleep per night."

Write a response in which you discuss what questions would need to be answered in order to decide whether the recommendation and the argument on which it is based are reasonable. Be sure to explain how the answers to these questions would help to evaluate the recommendation.

这个题目中，自然有许多问题。我们仅以样本问题为例，突破一下这个经典的常见的逻辑疑点：

样本的问题通常有二：1）容量；2）构成.

The first question regards the number of all advertising executives. If the number is considerably large, in tens of thousands, the number of executives involved in the recent study–300–may be inadequate to represent the possible tens of thousands of peers in the advertising industry. For example, the conclusion is hardly convincing, if it is drawn from the generalization from a mere 300 to a total of 100,000. ← 至此，样本的容量问题讨论完毕。接下来讨论样本的构成。→In addition, the composition of the 300 males and females is also unclear. It is therefore reasonable to question the representativeness of the 300 study participants in multiple dimensions regarding the composition, such as the whether the male-female ratio among those 300 is reasonable. Take this point as an example, if the ratio between male executives and the female counterparts in the whole advertising business is 2 to 1, this ratio should be adopted when the study gathers the 300 subjects. Likewise, questions, such as whether those 300 cover the whole range of ages, and whether they are from advertising agencies that have different scales of business and, thus, different loads of work per individual, should be asked. ← 的确，样本的构成问题可能比容量问题复杂些，因为考虑构成时的因素（不像容量只有人数多寡那么单纯）有许多。To wrap up the questions above, it may be implausible to draw the conclusion based on the 300 informants in the study.

样本问题，你get到了么？下一周，我们还会以这个题目为例，讲另一个经典的常见的逻辑疑点：研究方法问题。