The U.S. census is not perfect: thousands of Americans probably go unc

Hey All,

Looks like there's enough struggling with this one that it would pay for me to weigh in. Let's give it the red carpet treatment.

The U.S. census is not perfect: thousands of Americans probably go uncounted. However, the basic statistical portrait of the nation painted by the census is accurate. Certainly some of the poor go uncounted, particularly the homeless; but some of the rich go uncounted as well, because they are often abroad or traveling between one residence and another.
Which of the following is an assumption on which the argument above depends?

Conclusion: Basic stat portrait of census is accurate
Premise: Some poor uncounted, but also some rich
Assumption: The uncounted rich and poor are roughly equal. Rich and poor are emblematic of the portrait of other groups.

Notice I was able to come up with a couple of assumptions here. This is a pretty bad argument, so there might even be more. It's always helpful to think ahead as much as possible. I wrote both of these before looking at the answer choices, so I have an idea of what I'm looking for.

(A) Both the rich and the poor have personal and economic reasons to avoid being counted by the census.
PROBLEM: We don't care why people avoid the census, only how many of them do.

(B) All Americans may reasonably be classified as either poor or rich.
PROBLEM: This relates to my second assumption, but the language goes too far. We don't need all Americans to be classifiable as poor or rich, because even if there were Americans who could not be classified as poor or rich, the argument would not fall apart. It would become a little muddy (what about those middle class folks?), but we wouldn't have definitive proof that the census was bad.

(C) The percentage of poor Americans uncounted by the census is close to the percentage of rich Americans uncounted.
ANSWER: This relates to my first assumption, and is tough to figure out, so it helps to actually take apart the math a bit. Let's imagine that there are 100 people in the country, but we only end up counting 80. If 50 poor, 50 rich is reality and 50 poor and 30 rich are actually counted, we'd have missed 66% of the rich and 0% of the poor, and now our count doesn't provide an accurate portrait of the break down in America (which should have been 50/50, but is no 5/8ths versus 3/8ths). On the flip side, if we miss 10 poor and 10 rich (The same percentage of 50), our breakdown of the country's statistics is still accurate (40 and 40 out of 80, versus 50 and 50 out of 100), even though the hard numbers are wrong.

(D) The number of homeless Americans is approximately equal to the number of rich Americans.
PROBLEM: How many actual people there are in each category is immaterial here. We only care about percentage breakdowns.

(E) The primary purpose of the census is to analyze the economic status of the American population.
PROBLEM: The purpose of the census is immaterial, only its statistical results.

Hope that helps!

-t

My take is that B cud also have been a valid assumption,

But in the context of argument which talks about about the poor and rich people, the assumption shud be close to it.

in gMAT, its the matter of which is more correct rather than being absolutely correct.

My answer is C.

number of poor people = 150 ( acutally)

ppl counted = 120 missed = 30

number of rich people = 100
ppl counted = 80 missed = 20

actual health of nation = 150/100 = 3/2
counted health of nation = 120/80 = 3/2

census is same only when the percentage of missed people in both rich and poor categories is same..

IMO C.

B is an assumption for C,which in turn is the required assumption for the argument,which talks abt the 'the basic statistical portrait of the nation painted by the census is accurate'. To explain this, the next line is the reasoning 'Certainly some of the poor go uncounted, particularly the homeless; but some of the rich go uncounted as well, because they are often abroad or traveling between one residence and another.'

But this reasoning depends on the the assumption C.

Please correct if i am wrong.

C it is.

Census should be in proportion to the population (represent the population)

Population = 20% A + 30% B + 50% C
if lets assume 10% of each not counted (not number)
then it'll still represent the potrait of the nation with the ratio of popualtion 2:3:5

but if the equal number of each group are not counted ==> it'll distort the portrait of the nation.

This was a real tough one, and I might be overthinking it but ill give it a shot:

I was for C before I tried to explain my reasoning

Now I believe its D

Premise 1: Some Poor arent counted, particularly the homeless
Premise 2: Some Rich arent counted because they are often traveling

Assumption 1: You need to be home to counted
Assumption 2: The homeless arent counted because they dont have a home, the rich arent counted because they often arent at home
Assumption 3: The number of homeless is approximately the number of rich

Conclusion: Net effect on the census is zero

Am i assuming too much?

What is the OA?

I do not think so.
but you miss one information: "Rich people" is different from "rich people who often travel (until left uncount)".

(D) The number of homeless Americans is approximately equal to the number of rich Americans.-->in D, Homeless American=Rich American (wrong). There are some rich people who stay home.

To correct the (D): The number of homeless Americans is approximately equal to the number of rich Americanswho often travel (Now it can be the assumption. However, this corrected D means the same thing as C. does).

Fact1:The U.S. census is not perfect: thousands of Americans probably go uncounted.
Fact2:Certainly some of the poor go uncounted, particularly the homeless;
Fact3:but some of the rich go uncounted as well, because they are often abroad or traveling between one residence and another.
Conclusion:the basic statistical portrait of the nation painted by the census is accurate.

Paraphrased Assumption: The number of uncounted poor people = number of uncounted rich people.

Skim through the answer choices
C seems to be the closest.

Non necessary for getting to the answer but I will also examine why the other choices are wrong -
(A) Both the rich and the poor have personal and economic reasons to avoid being counted by the census. Out of Scope.
(B) All Americans may reasonably be classified as either poor or rich. Comes close but vague
(D) The number of homeless Americans is approximately equal to the number of rich Americans.We don't care how many are rich or poor we only care how many of those are unaccounted for
(E) The primary purpose of the census is to analyze the economic status of the American population.Probably an inference not an assumption but a very very close one since we are sort of assuming that Census is not merely counting people but it's counting people based on their economic status.

Hey Nusmavrik,

This is a dangerous piece of advice, but I'm throwing it out there anyway. Whenever you read an answer choice that just sounds logically ridiculous, be wary of it. (As in, don't totally leave your common sense at the door.) Would you need to base an argument on the fact that every single human being was either rich or poor? It seems unlikely, unless the argument was incredibly ridiculous. : )

-tommy

Lets say 100 people in America. 40 Rich and 60 Poor. Ratio is 2:3 -----> This is the statistical figure.
Now lets say 10% are uncounted in both the groups.

Rich = 0.9 * 40 = 36
Poor = 0.9 * 60 = 54

Ratio = 36/54 = 4/6 = 2/3 ------------> Statistical data is TRUE regardless of census.
C is the answer. You can try with another ratio and come with the same conclusion

B : classifies the people as rich or poor but does not explains why statistical data will be true.

D : You can prove this mathematically or assumption. Lets say 50 Rich and 50 Poor. Ratio 1:1
If the census discounts different number in the two group then

Rich = 46
Poor = 40
Ratio = 46 : 40 which is not the same as 1:1
So D does not explains why the statistical data is the same. In fact D weakens the argument.

Looks like a bad question. The question should have been framed as an inference question than as an assumption question. The reason is in an inference you derive something based on what is given. You do not need an additional fact. Only when it is an additional fact independent of what is given then it becomes an assumption.

Let us look at the relevant statements:

Statement 1: Certainly some of the poor go uncounted, particularly the homeless; but some of the rich go uncounted as well,
Statement 2: the basic statistical portrait of the nation painted by the census is accurate.

So statement 2 looks more like a conclusion drawn from statement 1. Thus if both the above statements are true then we can infer that equal percentage of rich and poor go uncounted without relying on any additional information. Choice C is not an independent fact to make it an assumption.
_________________

Another subtle difference between assumption and inference is that given the argument an inference is derived from the argument whereas an assumption is an independent fact.

Example of an assumption

Premise: Roger is a rich man

Conclusion: Roger does not follow the law

In coming to the conclusion we make the assumption that rich men do not follow law. The correctness of the argument is derived from the assumption. The premise by itself cannot make the conclusion correct. You need the assumption.


In our case the statement that both some rich and some poor go uncounted along with the statement that the basic statistical portrait of the census is accurate imply that any one group is not disproportionately considered in the census. You do not need the statement that the percentage of rich left out is the same as that of the poor left out for supporting the argument.
_________________

The crux of this problem lies in identifying the meaning of "basic statistical portrait of the nation"
Once you have identified what the argument is saying, then answer is easy.

Basic statistical Portrait of a nation could mean many things :-
people under 30 Years as compared to people above 30 years
people in rural area vs. people in urban area
ratio of average rainfall this decade to average rainfall last decade
ONE THING IS CLEAR FROM THE ABOVE THREE EXAMPLES, THE CONCEPT OF RATIO WILL COME INTO PLAY

Now since the argument uses this fancy term in reference to US Census and its shortcoming in properly counting the poor and the rich, we can assume that "this basic portrait of nation" is about number or percentage of rich and poor people. SO WHAT EXACTLY IS IT TALKING ABOUT-NUMBER OR PERCENTAGE?
The argument accepts that the census is flawed because the number of rich and poor is not correctly reported, but then it says the general picture is correct.
How can this happen. Only when you take percentage into acount.
For example
there are 100 Rich and 2000 Poor people. IF the census would be correct then the ratio of \(\frac{rich}{poor}\) would be \(\frac{100}{2000}\) = \(\frac{1}{20}\)
And 10 % of rich \(100 *\frac{10}{100}\) = 10 Rich are not reported meaning only 90 rich are counted in census
and 10 % of poor \(2000 *\frac{10}{100}\)=200 Poor and not reported meaning only 1800 poor are counted in census

The ratio however will still be the same \(\frac{RICH}{POOR}\)= \(\frac{90}{1800}\) =\(\frac{1}{20}\)

So OPTION C is correct which says
(C) The percentage of poor Americans uncounted by the census is close to the percentage of rich Americans uncounted.



_________________

A- reasons to avoid being counted is irrelevant.
B- This is not true. The argument considers rich and poor people of US. This does not mean that all people can be classified into one of the two categories.
C- This accurately states the assumption of the argument. Since the percentage of both the category of people are equal, statistical portrait of census is true.
D- this is not true. Number of homeless Americans uncounted can be equal to the number of rich Americans uncounted. But,the number of the poor homeless Americans is not necessarily equal to the number of rich Americans.
E- Primary purpose of census is irrelevant. Hence (c).

A is irrelevant. The motives that the rich and poor have for avoiding the census are immaterial. B is unnecessary, whether all Americans can be classified as rich or poor doesn’t really affect this question. It is also quite absolute. D is also irrelevant as we are only concerned with percentage breakdowns here. E is irrelevant because the purpose of the census is immaterial. Whatever the purpose is, we know what the results are. So, by PoE, C is the right answer.

I selected B because if there are "middle-class", the poor, middle class, and rich people counts are require to decrease by the same proportion to make the basic statistical portrait of the nation accurate.

And if this is the case, even if C is right, the conclusion may not hold.
e.g. P:MC:R = 30:20:10
if P and R both decreased by 10%, the surveyed ratio become 27:20:9, then the basic statistical portrait would be incorrect.

Could anyone please further advise how I could evaluate B and C with the "middle class" consideration? Thanks in advance

(A) Both the rich and the poor have personal and economic reasons to avoid being counted by the census. in reversal it becomes that both dont have personal and economical reasons so, its true that both dont have both the reasons each has only one reason to avoid being counted by the cencus. hence in reversal it does not weakening the argument. so it can not be the assumption.

Hello from the GMAT Club VerbalBot!

Thanks to another GMAT Club member, I have just discovered this valuable topic, yet it had no discussion for over a year. I am now bumping it up - doing my job. I think you may find it valuable (esp those replies with Kudos).

Want to see all other topics I dig out? Follow me (click follow button on profile). You will receive a summary of all topics I bump in your profile area as well as via email.
_________________