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.
結論說有裝測速器的車比較容易超速
The conclusion drawn above depends on which of the following assumptions?
裝了測速器應該比較不會被開罰單,但是卻還是被開,也就是說那些被開罰單的人是真的愛超速!
簡單的來說 觀察: 被開罰單的人(A)= 裝測速器的人(B) 而結論是裝測速器(B)=愛超速(C)
要如何推論出(B)=(C)呢? 前提就是被開罰單的人(A)=愛超速(C)
(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.(X)
(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.(被開罰單的人比沒被開罰單的人容易超速)
(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.(X)
(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.(X)
(E) Drivers on Maryland highways exceeded the speed limit more often than did drivers on other state highways not covered in the report. (X)