Re: [問題] 請問有關CR的assumption題

[aaaaaakoyasu (六點半天色還沒亮)]

※ 引述《betterman720 (betterman)》之銘言：
: 以PP2-CR-40舉例好了
: 40.     (32847-!-item-!-188;#058&007552)
: 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.
: 答案是(B)
: 想很久還是不知道為什麼
: 有牛人願意解惑嗎?
: 小弟先謝過了^^

題目：
該州3%的人裝有雷達探測器
該州被開超速罰單的人33%裝有雷達探測器
作者結論：
裝有雷達探測器的人比沒裝的人較會超速

前提是：
被開超速罰單的人都是因為常超速才會被開單，
如果是偶爾才超速卻常被開單的話（＝被開單的都是很少超速的人），
整篇的立足點就消失了。

所以答案是B

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推 betterman720:謝謝~~~^^
推 error404joe:不好意思 我還是想不懂 結論跟前提有什麼關係 為什麼
→ error404joe:被開單都是很少超速的話 立足點就消失了 裝雷達的人也
→ error404joe:可能不常超速啊
雖然只有3%的人裝雷達探測器，但是被開單的人中卻有33%的人都裝有雷達探測器，
作者的結論是裝有雷達探測器的人較會超速。

裝雷達探測器的人->較會超速->所以常被開單

所以要成立作者的結論的前提是因為被開單的人都是因為常超速才被開單，
而不是常被開單的人都是因為偶爾超速卻"倒楣"被開單。

這樣解釋有比較清楚嗎？@@

若還是不清楚我明天睡醒再想方法解釋，今天算太多數學，頭昏昏腦頓頓的~"~
※ 編輯: aaaaaakoyasu    來自: 65.29.188.149        (10/26 14:54)
推 error404joe:懂了 感謝!其實跟雷達比較沒關係 而且我一直在上面打
→ error404joe:轉 感激!!
→ aaaaaakoyasu:Not a problem :)