12. The following appeared as part of a promotional campaign to sell advertising¹ space in the Daily Gazette to grocery stores in the Marston area.
“Advertising the reduced price of selected grocery items in the Daily Gazette will help you increase your sales. Consider the results of a study conducted last month. Thirty sale items from a store in downtown Marston were advertised in the Gazette for four days. Each time one or more of the 30 items was purchased, clerks asked whether the shopper had read the ad. Two-thirds of the 200 shoppers asked answered in the affirmative. Furthermore, more than half the customers who answered in the affirmative spent over $100 at the store.”
Discuss how well reasoned... etc.
在把Gazette日报的广告版向Marston地区的蔬菜商销售的计划：
在Gazette日报宣传特价菜会帮助你提高销售额。考虑上月的一个研究的结果。Marston中心区的一个商店的30种特价菜在Gazette做了4天广告。每当有特价菜被卖出，职员就问顾客是否读过广告。200顾客中的2/3回答是肯定的。而且，持肯定回答的顾客中有超过一半的人在店里的消费超过100美元。
读了广告之后买了特价菜，并不意味着是因为看了广告才去买特价菜。可以有很多因素促使消费者买特价菜。此外作者是想说可以提高总体销售水平但他的论证实际根本没有涉及这一点。起码要给出没有做广告时候一天销售额和做了广告之后的对比。
1，       没有对比没做广告和做广告后sale的对比，只说了消费的人看了广告，并且一半支付了100以上，很可能没有广告的话也一样。
2，       没有建立起因果联系，虽然买东西的人看了广告，但是不代表是因为广告而买的。很可能不存在此因果联系。
3，        没有排除他因。如过sale上升了，那也有可能是别的原因导致的，而不是因为广告。比如thanks giving，比如商品质量提高，花样更多，比如最近的经济很好等等。

The conclusion of this argument is that advertising the reduced price of selected items in the Daily Gazette will result in increased sales overall. To support it, the author cites an informal poll conducted by sales clerks when customers purchased advertised items. Each time one or more of the advertised items was sold, the clerks asked whether the customer had read the ad. It turned out that two-thirds of 200 shoppers questioned said that they had read the ad. In addition, of those who reported reading the ad, more than half spent over $100 in the store. This argument is unconvincing for two reasons.
To begin with, the author’s line of reasoning is that the advertisement was the cause of the purchase of the sale items. However, while the poll establishes a correlation² between reading the ad and purchasing sale items, and also indicates a correlation, though less significantly, between reading the ad and buying non-sale items, it does not establish a general causal relationship between these events. To establish this relationship, other factors that could bring about this result must be considered and eliminated. For example, if the four days during which the poll was conducted preceded Thanksgiving and the advertised items were traditionally associated with this holiday, then the results of the poll would be extremely biased³ and unreliable.
Moreover, the author assumes that the poll indicates that advertising certain sale will cause a general increase in sales. But the poll does not even address the issue of increased overall sales; it informs us mainly that, of the people who purchased sales items, more had read the ad than not. A much clearer indicator⁴ of the ad’s effectiveness would be a comparison of overall sales on days the ad ran with overall sales on otherwise similar days when the ad did not run.
In sum, this argument is defective⁵ mainly because the poll does not support the conclusion that sales in general will increase when reduced-price products are advertised in the Daily Gazette. To strengthen the argument, the author must, at the very least, provide comparisons of overall sales reports as described above.