It is unlikely to be mere speculation that the number of seats in a

Question

It is unlikely to be mere speculation that the number of seats in a typical private school in Manidia, which has both private and public schools, was increased in the 1990s and 2000s. Supporting evidence can be found in the outcomes of two studies, one conducted in 1990 for which the researchers unbiasedly selected around 50% of the private schools and the other in 2010 on the same schools. The studies found that the mean number of seats in those schools in 1990 was 800 and in 2010 was 1000.

Which of the following points to the most serious logical flaw in the reasoning above?

A. The studies did not take the median number of the seats which would have been a better measure of the number of seats in a private school.
B. The findings of the studies contain information of only those private schools that were present in 1990.
C. The mean number of students in Manidia’s schools, both public and private increased around the 1990s and 2000s.
D. During the period covered by the studies, many of the private schools admitted children of employees who had recently moved to Mandia.
E. The average number of seats offered for admission in a school is not the correct parameter for judging the actual number of students studying in a school at any given point.

Anshuman0902 · Answer

hey expert !
quiet confuse between C and B 
end up marking C .
where am i getting wrong

svasan05 · Answer

Pre-thinking:

Conclusion:  It is unlikely to be mere speculation that the number of seats in a typical private school in Manidia, which has both private and public schools, was increased in the 1990s and 2000s.

Premises on which it is based:

In 1990, 50% of private schools in Manidia were selected. The average number of seats in these schools was 800 in 1990 and 1000 in 2010.

While taking the mean of number of seats of a randomly selected sample of schools is a reasonable approach, the clear problem in the approach of the studies is that the same schools that were sampled in 1990 and 2010 - two years far apart in time. A lot could have transpired in this time - there could be more schools or less, with varying seat strengths. In other words, the underlying assumption that the sample of schools is representative of all schools, which is reasonable for the year 1990, no longer holds for 2010 since so much time had passed. For example, it is possible that a large number of schools were opened close to 2010 that would have relatively fewer number of seats. Ideally, a fresh random sample should have been taken in 2010.

Let us look at the answer options.

A. The studies did not take the median number of the seats which would have been a better measure of the number of seats in a private school.  This is true if there are large outliers - we do not know if that is the case. Eliminate.

B. The findings of the studies contain information of only those private schools that were present in 1990.  Correct answer and consistent with out pre-thinking.

C. The mean number of students in Manidia’s schools, both public and private increased around the 1990s and 2000s.  If this is true, it bolsters the conclusion, since it is reasonable to assume that total seats are in direct proportion to number of students. Also, a "flaw" must be inherent in the argument and not new information brought in from outside. Eliminate.

D. During the period covered by the studies, many of the private schools admitted children of employees who had recently moved to Mandia.  This does not impact the conclusion as it does not address the number of total seats at all. Also, a "flaw" must be inherent in the argument and not new information brought in from outside. Eliminate.

E. The average number of seats offered for admission in a school is not the correct parameter for judging the actual number of students studying in a school at any given point.  Even if this were true, the argument is made on the basis of average number of seats and not average number of seats offered for admission. Therefore, this cannot be the flaw. Eliminate.

Hope this helps.

Raman109 · Answer

Understanding the argument - 
It is unlikely to be mere speculation that the number of seats in a typical private school in Manidia, which has both private and public schools, was increased in the 1990s and 2000s. - Conclusion. It is likely true that the number increased. 
Supporting evidence can be found in the outcomes of two studies, one conducted in 1990 for which the researchers unbiasedly selected around 50% of the private schools and the other in 2010 on the same schools. The studies found that the mean number of seats in those schools in 1990 was 800 and in 2010 was 1000. - supporting premise.

Option Elimination - Flaw

A. The studies did not take the median number of the seats which would have been a better measure of the number of seats in a private school. - What is the correct way is not the contention. We need to find the flaw in the current way. Distortion.

B. The findings of the studies contain information of only those private schools that were present in 1990. - ok. Suppose in 1990 we had 1000 schools and picked 500 schools randomly. But in 2000, there were 5000 schools and the average number per school is, say, 100 students. So the 500 we chose in 1990 are not representative of the new 4000 opened. It's a representation flaw. Ok.

C. The mean number of students in Manidia’s schools, both public and private increased around the 1990s and 2000s. - We already know. Distortion. 
 
D. During the period covered by the studies, many of the private schools admitted children of employees who had recently moved to Mandia. - We are given the mean and what background students were admitted is out of scope.

E. The average number of seats offered for admission in a school is not the correct parameter for judging the actual number of students studying in a school at any given point.- weather the method is correct or not is not an issue. We need to find the flaw in the current method. Distortion.

VerbalBot · Answer

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It is unlikely to be mere speculation that the number of seats in a

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