[求助]陈向东逻辑 反对题52

amo

52 As a promotional experiment, Omega Company distributed four million catalogs. In one of the two versions of the catalog, the description of each for sale mentioned a “Made by Hand” label. The number of purchases from consumers receiving that catalog was twenty percent greater than the number of purchases from consumers receiving a catalog that did not mention the label. Thus, the mention of label stimulated sales.

Which of the following, if true, could best be used to challenge the conclusion drawn above?

(A)         Consumers receiving the catalog mentioning the label had previously purchased items from Omega Company by mail but consumers receiving the other catalog had not.

答案A

为什么A是答案？是如何得出这个答案的呢？

weiyu

52 As a promotional experiment, Omega Company distributed four million catalogs(background). In one of the two versions of the catalog, the description of each for sale mentioned a “Made by Hand” label(evidence1). The number of purchases from consumers receiving that catalog was twenty percent greater than the number of purchases from consumers receiving a catalog that did not mention the label(evidence2). Thus, the mention of label stimulated sales(conclusion).

Logic layout: evidence2->conclusion.

Choice A indicates essential difference of the consumers who recieve the 2 catalogs respectively, consequently, the argument cannot explain evidence2 is caused by label rather than by the essential difference between 2 group of consumers.