The average age of chief executive officers (CEOs) in a large sample

The question states in a large sample the CEO's are on average 8 years older than they were 20 years ago. Because the question already tells you that a large sample is used, knowing the exact number of firms in the survey to determine whether the study is viable or not is not necessary. Also, so what if you know the number of companies that took the survey. That information is useless because you don't know how many firms out of how many considered took the survey. For example, if you know 50 firms took the survey. Is it 50 out of 100 firms or 50 out of 10,000.

You have to show that in fact CEOs aren't getting older. Good way to do it is to attack the evidence - that is the survey of 57 companies. Maybe these companies are not representative of market in general, so we cannot deduce the general trend based solely on these companies.

(C) does exactly the same - if the survey includes only the companies with history of 20 years or more, it cannot be representative of all companies and cannot describe general trend.

C strengthens the conclusion. The sample should be the same and should consist of companies which have been in business for at least 20 years; otherwise, how could any conclusion be drawn ?

I would pick A.

Please indicate the source.

@imadkho,

The question is asking us which of the following would cast the most doubt on the conclusion. The conclusion of course rests on the sample size, so when you ask how the argument can draw a valid conclusion, that's the whole point: the argument cannot make a valid conclusion.

Specifically, when it makes its conclusion regarding companies today, it fails to take into account those companies that weren't around 20 years ago. Therefore, the conclusion cannot be valid. (C) speaks to this.

(A) only talks about starting dates. We do not care when CEOs started, but old they are now. So even if a CEO started 20 years ago, he/she could still only be 45 years-old vs. one who started yesterday at a startup but is 60 years old (assuming start ups still employ someone who is 60 )

No. The argument only says that CEOs tend to be older now. It is not the same as 'companies are appointing older CEOs now.'

Then I agree with C, but I still feel A is a contender.
My explanation: Suppose the survey companies analyse the age of CEOs.The sample consists of 100 CEOs among whom 80 were made the CEO at the age of 45. Now these CEOs are now aged 57, but still can you say that now a days CEOs are getting older. Obviously not!

We are talking about 2 points in time. 20 yrs back the avg age was 40. Today the avg age is 60. The CEOs are definitely getting older. The point is not why they are getting older. The company has retained a 60 yr old for the top position. It has not brought in a young gun. They have the freedom to bring in a new guy whenever they desire. It doesn't matter why the company has retained the old guy - his experience or his performance whatever. What matters is that at this point, its CEO is a 60 yr old and the company is fine with it. It is not a lifetime position awarded to the CEOs. If, on average, the companies are happy with the older lot, it means the CEOs are getting older now.

Very good question in term of statistic logic. C is correct.

What's wrong if the sample does not represent characteristics of the whole group.
Premise 1: the average age of CEOs of the companies 20 years ago was 49 (57 - 8).
Premise 2: the average age of CEOs of the same companies is 57 now.
Conclusion: Average age of CEOS in general is older

Wrong sampling technique because the companies that were chosen do not represent characteristics of the whole group. For instance, new established companies (less than 20 years old) often have young CEOs.

I'm happy to help.

IMPORTANT NOTES:
This question is about “sampling” like the technique used in statistic (Quant).
KEY point is: the sample used to generalize the whole set MUST be comprehensive enough.

ANALYZE THE STIMULUS:
Fact: The average age of chief executive officers (CEO’s) in a large sample of companies is 57.
Fact: The average age of CEO’s in those same companies 20 years ago was approximately eight years younger.
Conclusion: CEO’s in general tend to be older now.

Which of the following casts the most doubt on the conclusion drawn above?

ANALYZE EACH ANSWER:

(A) The dates when the CEO’s assumed their current positions have not been specified.
Wrong. A may weaken or NOT. What if the CEO’s are appointed to their position at younger ages. Thus, A does not weaken the conclusion.

(B) No information is given concerning the average number of years that CEO’s remain in office.
Wrong. The average number of years in office DIFFERS from how old the CEO’s are when they are appointed to their positions.

(C) The information is based only on companies that have been operating for at least 20 years.
Correct. C weakens the conclusion by showing that the sample used to GENERALIZE the conclusion is not comprehensive. The argument just uses information of companies operating for at least 20 years to make a conclusion for every CEO’s.

(D) Only approximate information is given concerning the average age of the CEO’s 20 years ago.
Wrong. The conclusion may be still correct if the information of the average age of the CEO’s 20 years ago is COMPRESHENSIVE enough. It means the sample can represent the whole set.

(E) Information concerning the exact number of companies in the sample has not been given.
Wrong. Out of scope. We do not need information about how many companies in the sample. There are 20, or 200. We don’t know. Thus, E does not help.

Hope it helps.

Why not E. If the number of the companies used for base of calculation of the average is different between the years, then the conclusion is wrong and weaken the argument. Still C is not understandable as it does not give us any hidden assumption regarding generalization of the companies to all market. I think we can not make such assumption.

(E) is not correct.
The argument gives the following information:
"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."

We know the sample is large and the same companies were a part of the research 20 yrs back too. As for the number of companies being a bit different, I don't see how that is a problem - say there were 100 companies last time and 90 this time (10 shut shop). These 90 are still representative of the previous 100.

The problem is that from this data we are generalizing - CEO’s in general tend to be older now.

What if these companies (which are at least 20 yrs old) are not representative of all companies. Then we cannot generalize. What if the newer companies have very young CEOs? Hence (C) weakens the argument.

I go with C too...but i would put the following as the reason for eliminating option E.
Explanation: In the beginning the author puts it as " a large sample of companies" and then later in the following sentence as " in those same companies". So the information regarding the exact number of companies doesnt really matter as the comparison is being done for the same group of companies.

Correct me if am wrong.
Thanks.

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I think i deserve a kudos..if am correct!!!

he 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?

Good question and this sort of reasoning is used in real life also.
Conclusion : CEOs are older now in general .
Arrived at this conclusion : By comparing ages of a specific group.
Assumption : This particular group is representative of the overall industry 20 years ago and even now.

Break this and you have your weaken answer. Say the sample excludes all the companies whose ceo is in his 20s. Then it is invalidated as it is not accurate representation of entire industry.

(A) The dates when the CEO’s assumed their current positions have not been specified. ---> I am not interested in writing history of a company . My conclusion is about ceos are older
(B) No information is given concerning the average number of years that CEO’s remain in office. ---> It is not talking about sample and ceos remain in office so what do get about if they are getting older or younger. Nothing
(C) The information is based only on companies that have been operating for at least 20 years. --> Breaks the sample. Think of it this way, in the last 20 years, if so many companies with young ceos have started operations then the sample is not taking these new changes but sticking to its old companies that were there 20 years back. So average age of ceo at present is lesser. Thus, this is right answer.
(D) Only approximate information is given concerning the average age of the CEO’s 20 years ago. --> ofs
(E) Information concerning the exact number of companies in the sample has not been given. --> ofs

IMHO (C) , since -

1. Premises talks about a large survey of companies and age of CEOs of those companies 20 years ago
2. Conclusion talks about the avergae age of CEOs ( In General )

This is a weaken question. We have to find the conclusion and weaken it.

Premises:

The average age of CEOs 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.

Conclusion: CEO’s in general tend to be older now.

Notice what the conclusion says: CEOs IN GENERAL tend to be older now. How can you deduce something about CEOs in general now when you have researched CEOs of only those companies which were in operation 20 yrs ago too. What about all the companies that came up in the last 20 years? What if the CEOs of the younger companies are much younger. Then the conclusion weakens. Option (C) points out this flaw in the reasoning. Hence it weakens the conclusion.

Premises:

The average age of CEOs 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.

Conclusion: CEO’s in general tend to be older now.

(B) No information is given concerning the average number of years that CEO’s remain in office.

This is irrelevant. Does it matter whether the CEO's remain in office for 10 years or for 2 years? Point is, it doesn't matter whether the 20 companies have the same CEOs that they had 8 yrs ago or they change CEO's every year and have been hiring older CEOs. In any case, in those 20 companies CEOs are older today than they were 8 yrs ago. So option (B) does not weaken the conclusion.

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?

What is the main concern ? That CEO`s in (some) companies are not older now then 20 years ago in the same companies. IN OTHER WORDS NEED TO PROVE THIS BY WEAKENING THE CONCLUSION.


(A) The dates when the CEO’s assumed their current positions have not been specified. (not concerned with current positions. out of scope.)

(B) No information is given concerning the average number of years that CEO’s remain in office. ( not concerned with average numbrs of years.out of scope.

(C) The information is based only on companies that have been operating for at least 20 years. (hmm keep it - matches the main concern )

(D) Only approximate information is given concerning the average age of the CEO’s 20 years ago. ( not comcerned with average age. out of acope.

(E) Information concerning the exact number of companies in the sample has not been given. ( not concerned with exact number of companies. )


C by POE