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655-705 (Hard)|   Weaken|      
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A person is considered obese if her BMI i.e. Body Mass Index, a ratio 31 Jan 2023, 06:15
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55% (hard)

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64% (01:52) correct 36% (02:07) wrong based on 194 sessions

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A person is considered obese if her BMI i.e. Body Mass Index, a ratio of a person’s weight to square of her height, exceeds a certain number. In 1990, the average BMI of the population was just below the threshold level for obesity. However, in a recent survey conducted, it was found that the average weight was 10% more than that of the population in 1990. Given that there has not been any increase in average height of the population since 1990, the obesity levels in the country must have increased.

Which of the following, if true, would cast the strongest doubt on the conclusion drawn above?

(A) In another survey conducted, it was found that the average fat consumption by individuals in the country has decreased.
(B) All the participants in the survey were taller than an average citizen of the country
(C) The population of country has increased by more than 10% since 1990.
(D) Obese people have a shorter life span than other people.
(E) A major criterion for selecting participants in the survey was the willingness of the participants to actively participate in the survey.
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B
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A person is considered obese if her BMI i.e. Body Mass Index, a ratio 31 Jan 2023, 14:24
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My analysis:

The conclusion of the passage is the following: since the average weight is 10% more than in 1990 (when BMI was just below the obesity threshold), obesity must have been increased.

Which of the following, if true, would cast the strongest doubt on the conclusion drawn above?
We need to find a possibility that WEAKEN the argument's conclusion.

(A) In another survey conducted, it was found that the average fat consumption by individuals in the country has decreased.
This cast some doubts. Higher weight can be given by muscles for example, so the fact that there is lower consumption of fat it's promising to think that obesity has not increased. Let's keep A.

(B) All the participants in the survey were taller than an average citizen of the country
The fact that the participants are taller, does not infer that their weight is higher.

(C) The population of country has increased by more than 10% since 1990.
Does not give useful information. Average can remain the same even with 10% more population.

(D) Obese people have a shorter life span than other people.
No useful information, discard D.

(E) A major criterion for selecting participants in the survey was the willingness of the participants to actively participate in the survey.
No useful information, discard E.

In my opinion is A.
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A person is considered obese if her BMI i.e. Body Mass Index, a ratio 31 Jan 2023, 14:26
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The OA is neither A nor C :dontknow:
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A person is considered obese if her BMI i.e. Body Mass Index, a ratio 31 Jan 2023, 15:29
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A person is considered obese if her BMI i.e. Body Mass Index, a ratio of a person’s weight to square of her height, exceeds a certain number. In 1990, the average BMI of the population was just below the threshold level for obesity. However, in a recent survey conducted, it was found that the average weight was 10% more than that of the population in 1990.

Until now is the same thing: blah blah blah = increase body weight + the survey and in the gmat land the surveys are always suspicious


Given that there has not been any increase in average height of the population since 1990, the obesity levels in the country must have increased.


(A) In another survey conducted, it was found that the average fat consumption by individuals in the country has decreased.

who cares of another survey

(B) All the participants in the survey were taller than an average citizen of the country

taller tells us nothing about the body mass

(C) The population of country has increased by more than 10% since 1990.

the population overall is not relevant we need a certain cluster

(D) Obese people have a shorter life span than other people.

just another statistic or factor obese people live less than others

(E) A major criterion for selecting participants in the survey was the willingness of the participants to actively participate in the survey.

the willingness = biased = survey not reliable= the correct answer
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A person is considered obese if her BMI i.e. Body Mass Index, a ratio 01 Feb 2023, 01:40
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Interesting question!

A) Nope. This would only tell us about dietary changes, but does not tell us anything about the obesity levels.

B) Good choice. If this were true, then maybe the average weight increase of >10% might not actually lead to higher obesity levels. Recall that in the passage, BMI was taken as a determinant for obesity (weight/(height)^2)). Therefore, if the weight portion of the BMI formula increases, and there is also an increase in the height portion of the BMI formula, then there is the possibility that there is no change in the obesity levels or even a reduction (imagine if the average weight increases by 15%, but the average height doubled, the resulting BMI would be much lower.

C) Tempting, but this does not tell us anything about the average BMI of that country. This would only add more people to consider, but it can go either way. Imagine if all the new people were extremely heavy for their height? Then the average BMI would go way up, supporting the argument. If the opposite happens, then it would weaken. This cannot be a suitable answer. Out.

D) This is something that may be completely true, however it does not help in weakening the argument.

E) This is also a tempting choice. However, this fails compared to B. It states the "willingness of participants". This can go either way. It could be that the heavier people of the population did not want to participate, in which case the argument would be supported (the 10% weight increase represents the "least heavy" of the population, in this case). However, it could be that the heaviest people are more keen on participating, in which case the >10% weight increase is actually an overstatement of what is happening in the population. As option E can go either way, and requires a further assumption (that the heaviest people did not wish to participate) B remains the strongest choice.

B is the correct answer.
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A person is considered obese if her BMI i.e. Body Mass Index, a ratio 03 Feb 2023, 03:42
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For the same BMI, a taller person will weigh more. So, it is possible that the survey does not give the result.
Hence, B.
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