Critical Reasoning

According to a 1980 survey, ten percent of all United States citizens over the age of sixteen are functionally illiterate. Therefore, if the projection that there will be 250 million United States citizens over sixteen in the year 2000 is correct, we project that 25 million of these citizens will be functionally illiterate.

Which of the following, if true, would most weaken the conclusion drawn by the author of the passage above?

A) The percentage of high school graduates who do not go on to college has grown steadily over the past two decades.
B) from 1975 to 1980 there was a three percent decrease in the rate of functional illiteracy among United States citizens over the age of sixteen.
C) Many united states citizens included in the 1980 survey would also be included in the survey conducted in the year 2000.
D) Surveys that are improperly designed usually provide inaccurate results.
E) In 1980 sixty-five percent of all united States citizens were over the age of sixteen.

I was so sure of my answer, but after seeing the OA, i am damn confused. Unfortunately, I have only answer and no explanation. OA after discussion. Cheers!!

rahulg83

IMHO the answer is B

If you look at the argument it assumes that the illiteracy rate is constant... i.e. it does not change from year to year.. that is why the prediction is made that 25 mill out of 250 mill will be illiterate.

So we need to find the answer that weakens this assumption. If you look at B it says that there was actually observed a declining trend between 1975 and 1980 therefor the rate can NOT be believed as constant.. and the predictions could be erroneous.

As for other answers I guess more or less answers can be eliminated as for C here is what I think:

C. this is little bit tricky one, at first sight it seams that if this is true then the prediction is erroneous... i.e conclusion weakened.

I think this is wrong because : this argument is constructed this way: A is the fact, therefore B will be fact. so we need to attack this link... we need to prove that because A is the fact this does not prove that B will happen.

This sentence introduces a new information which is in no way connected with A and B link... (introducing new info is OK but it must be relevant). The info C offers does not seem actually to weaken the conclusion IMO.

Would be nice to know OA

I think correct answer is C

rahulg83 wrote:According to a 1980 survey, ten percent of all United States citizens over the age of sixteen are functionally illiterate. Therefore, if the projection that there will be 250 million United States citizens over sixteen in the year 2000 is correct, we project that 25 million of these citizens will be functionally illiterate.

Which of the following, if true, would most weaken the conclusion drawn by the author of the passage above?

A) The percentage of high school graduates who do not go on to college has grown steadily over the past two decades.
B) from 1975 to 1980 there was a three percent decrease in the rate of functional illiteracy among United States citizens over the age of sixteen.
C) Many united states citizens included in the 1980 survey would also be included in the survey conducted in the year 2000.
D) Surveys that are improperly designed usually provide inaccurate results.
E) In 1980 sixty-five percent of all united States citizens were over the age of sixteen.

I was so sure of my answer, but after seeing the OA, i am damn confused. Unfortunately, I have only answer and no explanation. OA after discussion. Cheers!!

My initial choice was B but I had look in deeper and then:

IMO A. My reasoning is rather strange

A-> If percentage is increasing every year then the argument falls apart.If this was just numbers instead of % , then we can negate A off the choices.
B-> Ok, we have a decrease in the time span before the survey but that does not prove that it cannot be constant. Moreover it need not be constant since once year we can have few and the next year we can have more illiterates to compensate for the loss and still arrive at the 250 million.

C-> very tricky option.Again does not concretely tell me that final numbers cannot be reached.

D And E to me seems out of scope.

OA please . Awesome question by the way. Where did u find it?

IMO C

IMO B. I don't understand why people are choosing C. Unless the conclusion stated that there would be 25 million new functional illiterate people in the U.S. I don't see how C weakens an argument. The assumption that the conclusion is dependent upon is that if the U.S. population grows then there would be the same percentage of functional illiterates. In order to weaken the argument, you need to choose an answer that cast doubt about the rate of functional illiterates remaining the same.

OA is B, but i don't understand how. Even after reading the above posts, i am not convinced. Even if we assume that from 1975 to 1980 illiteracy rate declined, this doesn't mean that it will again decline or increment, for that matter (this can't be inferred for period 1980-2000)..as amazonviper pointed out..

rahulg83 wrote:OA is B, but i don't understand how. Even after reading the above posts, i am not convinced. Even if we assume that from 1975 to 1980 illiteracy rate declined, this doesn't mean that it will again decline or increment, for that matter (this can't be inferred for period 1980-2000)..as amazonviper pointed out..

Can anyone clear our concerns on this..btw can anyone tell me where we can find 1000CR???

rahulg83 wrote:OA is B, but i don't understand how. Even after reading the above posts, i am not convinced. Even if we assume that from 1975 to 1980 illiteracy rate declined, this doesn't mean that it will again decline or increment, for that matter (this can't be inferred for period 1980-2000)..as amazonviper pointed out..

rahulg83, you are correct about saying that ' this doesn't mean that it will again decline' but the point is that if B is true we can not be so sure too that it will not i.e. stay constant.

that's the point: the conclusion is weakened i.e. it is shown that the conclusion is not 100% strong... think about it... we are not proving that the result described in conclusion can never happen what we are doing is showing that conclusion is just not that strong i.e. we are weakening it. we are showing that the result MAY NOT be just as it is described in conclusion.

amazonviper wrote:

rahulg83 wrote:According to a 1980 survey, ten percent of all United States citizens over the age of sixteen are functionally illiterate. Therefore, if the projection that there will be 250 million United States citizens over sixteen in the year 2000 is correct, we project that 25 million of these citizens will be functionally illiterate.

Which of the following, if true, would most weaken the conclusion drawn by the author of the passage above?

A) The percentage of high school graduates who do not go on to college has grown steadily over the past two decades.
B) from 1975 to 1980 there was a three percent decrease in the rate of functional illiteracy among United States citizens over the age of sixteen.
C) Many united states citizens included in the 1980 survey would also be included in the survey conducted in the year 2000.
D) Surveys that are improperly designed usually provide inaccurate results.
E) In 1980 sixty-five percent of all united States citizens were over the age of sixteen.

I was so sure of my answer, but after seeing the OA, i am damn confused. Unfortunately, I have only answer and no explanation. OA after discussion. Cheers!!

My initial choice was B but I had look in deeper and then:

IMO A. My reasoning is rather strange

A-> If percentage is increasing every year then the argument falls apart.If this was just numbers instead of % , then we can negate A off the choices.
B-> Ok, we have a decrease in the time span before the survey but that does not prove that it cannot be constant. Moreover it need not be constant since once year we can have few and the next year we can have more illiterates to compensate for the loss and still arrive at the 250 million.

C-> very tricky option.Again does not concretely tell me that final numbers cannot be reached.

D And E to me seems out of scope.

OA please . Awesome question by the way. Where did u find it?

I chose B, A was the 2nd possibility but it says "over the age of 16" which means they could be 38, 65, etc. Also, nowhere in the passage does it mention/justify high school education equating to being illiterate and college education equating to literate therefore I eliminated it

the premise and conclusions are easily confused here.

conclusion: '10% of the population over 16 will be illiterate'
premises: '10% of population in 1980 was illiterate'
assumption: 'the rate of illiteracy will stay constant'.

B challenges the assumption (by widening the gap between premise and conclusion)...I incorrectly thought at first that weakening meant guaranteeing that the conclusion doesn't hold. Weakening simpy widens the gap by challenging the assumption so that it needn't be true (althogh it could be).

This one isnt' that difficult..assumptions questions are much worse
B is clear choice. If true it offers an argument which weakens the original argument and projections that 20% of 250 milion people will be literate, hence 25 milion. But what if the rate of 10% decreases over the next ten years and you have 5% of population over 16 which is literate? This weakens the argument.

rahulg83 wrote:According to a 1980 survey, ten percent of all United States citizens over the age of sixteen are functionally illiterate. Therefore, if the projection that there will be 250 million United States citizens over sixteen in the year 2000 is correct, we project that 25 million of these citizens will be functionally illiterate.

Which of the following, if true, would most weaken the conclusion drawn by the author of the passage above?

A) The percentage of high school graduates who do not go on to college has grown steadily over the past two decades.
B) from 1975 to 1980 there was a three percent decrease in the rate of functional illiteracy among United States citizens over the age of sixteen.
C) Many united states citizens included in the 1980 survey would also be included in the survey conducted in the year 2000.
D) Surveys that are improperly designed usually provide inaccurate results.
E) In 1980 sixty-five percent of all united States citizens were over the age of sixteen.

I was so sure of my answer, but after seeing the OA, i am damn confused. Unfortunately, I have only answer and no explanation. OA after discussion. Cheers!!

meant b

C seems to be the best choice here