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 reqularly 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 ecxeeding 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
Evidence:
3% dirvers with radar detectors.
33% of those with radar detectors ticketed for exceeding speed limit.
Conclusion:
Drivers with radar detectors are more likely to exceed the speed limit regularly than driver without….
The only information provided is about the percentage of vehicles equipped with radar and the percentage of ticketed vehicles equipped with radar; the conclusion, however, makes a sweeping generalization about the regular driving behavior of individuals with radar-equipped vehicles.
An as analogy: 'The number of reported laptop thefts on campus increased by 10% from last year to this year. Therefore, more laptops have been stolen from campus this year than last year.'
The assumption here is that REPORTED laptop thefts are meaningfully correlated with ACTUAL laptop thefts. Without this association, the logic falls apart. The same is true for the tickets issued vs. regular speeding in this problem.作者: cattery 时间: 2010-4-1 06:57
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 (for exceeding the speed limit)
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 reqularly than are drivers who do not.
