A recent report determined that although only 3 percent of drivers on Maryland highways equipped their vehicles with radar detectors, 33 percent of all vehicles ticketed for exceeding the speed limit were equipped with them. Clearly, drivers who equip their vehicles with radar detectors are more likely to exceed the speed limit regularly than are drivers who do not.
The conclusion drawn above depends on which of the following assumptions?
171. A recent report determined that although only three percent of drivers on Maryland highways equipped their vehicles with radar detectors, thirty-three percent of all vehicles ticketed for exceeding the speed limit were equipped with them. Clearly, drivers who equip their vehicles with radar detectors are more likely to exceed the speed limit regularly than are drivers who do not. The conclusion drawn above depends on which of the following assumptions? (A) Drivers who equip their vehicles with radar detectors are less likely to be ticketed for exceeding the speed limit than are drivers who do not. (B) Drivers who are ticketed for exceeding the speed limit are more likely to exceed the speed limit regularly than are drivers who are not ticketed. (C) The number of vehicles that were ticketed for exceeding the speed limit was greater than the number of vehicles that were equipped with radar detectors. (D) Many of the vehicles that were ticketed for exceeding the speed limit were ticketed more than once in the time period covered by the report. (E) Drivers on Maryland highways exceeded the speed limit more often than did drivers on other state highways not covered in the report.
答案B。我的理解是B说明sample代表全部,不知对不对?可是,我觉得A也有道理 - vechiles with radar detectors不容易被抓住,不是也证明结论吗?
文中描述的是:the percent (of drivers who equip their vehicles with radar detectors exceed the speed limit regularly) is greater than that of drivers who do not. 强调数量 即:isolated occasions when drivers exceed the speed limit
而结论drivers who equip their vehicles with radar detectors are more likely to exceed the speed limit regularly than are drivers who do not.强调频率:concerns regularly exceeding the speed limit
这两个概念中间需要桥梁,即rivers who are ticketed for exceeding the speed limit are more likely to exceed the speed limit regularly than are drivers who are not ticketed