[問題]大全4-18

[angelat]

大全-4-18. The average age of chief executive officers (CEO’s) in a large sample of companies is 57. The average age of CEO’s in those same companies 20 years ago was approximately eight years
younger. On the basis of those data, it can be concluded that CEO’s in general tend to be older
now.
Which of the following casts the most doubt on the conclusion drawn above?
(A) The dates when the CEO’s assumed their current positions have not been specified.
(B) No information is given concerning the average number of years that CEO’s remain in office.
(C) The information is based only on companies that have been operating for at least 20 years.
(D) Only approximate information is given concerning the average age of the CEO’s 20 years ago.
(E) Information concerning the exact number of companies in the sample has not been given.

這一題答案是C
我自己寫的答案是B
我想的是：
如果一個CEO做了很久都沒有換，他的年紀就會影響到CEO的平均年紀，於是CEO的平均年紀就會增加，所以我選B，請問這樣想錯在哪裡呢？

[hsyeng]

平均年紀是57 同樣的公司樣本 20年前的CEO小8歲 下結論：現在的比較老
問weaken
我覺得這題是樣本的問題 不可以以偏蓋全 因為這個調查的公司都是必須超過20年的 不能代表全部 可能較年輕的公司CEO都超年輕(5歲) 那平均值就會被拉下來了

而B題目給的是年齡 與任期無關 作很久不代表老 極端一點可以8歲就當CEO阿

大家討論吧～

[angelat]

我瞭解了
謝謝