Critical Reasoning

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?
(A) Both the rich and the poor have personal and economic reasons to avoid being counted by the census.
(B) All Americans may reasonably be classified as either poor or rich.
(C) The percentage of poor Americans uncounted by the census is close to the percentage of rich Americans uncounted.
(D) The number of homeless Americans is approximately equal to the number of rich Americans.
(E) The primary purpose of the census is to analyze the economic status of the American population.



Can you guyz help me in identifying the premise and conclusion in the above argument. Experts please help!!
According to me the sentence after the word 'Certainly' is the conclusion and the rest as premise.

The conclusion is "However, the basic statistical portrait of the nation painted by the census is accurate."

I have two REALLY GOLDEN tips for you that you can apply throughout critical reasoning. Ready?

1) The first sentence will not be the conclusion here because it is followed by "however." When you have a hard transition like "however, yet, but, on the other hand, this cannot be true, etc." then the conclusion basically cannot come before that transition because the transition is a form of negation. If I were to say "some people will tell you never to apply for the third round, but..." you know that I am going to negate that phrase in the rest of the argument. So, not only the conclusion, but also the main evidence for that conclusion will need to come before the hard transition.

(This applies to strengthen, weaken, method of reasoning, bold-faced, assumption and so forth, just not to inference questions where there usually is no conclusion.)

2) If you are in doubt as to which statement is the conclusion you can use my soon-to-be famous "WHY? TEST." The main conclusion is the one that you can ask why about and the rest of the argument basically provides an answer.

Let's apply this technique to the question at hand:

You identified, "Certainly some of the poor go uncounted, particularly the homeless" as the conclusion (or perhaps you meant the part after the semicolon as well, but it does not matter). If you ask "Why do some of the poor go uncounted? The answer is NOT "because the basic statistical portrait of the nation painted by the census is accurate." That sentence does not support your proposed conclusion.

Now try my proposed conclusion, WHY is "the basic statistical portrait of the nation painted by the census is accurate?" Because some of the poor go uncounted, particularly the homeless, but some of the rich go uncounted as well..." So you can see that everything after the HOWEVER transition supports the conclusion that I have named above, while it does not work in the opposite direction. (Do not worry about anything before the "however" because as I mentioned the sentence before that has been negated so it is not a part of what we are looking at here.

Signal words are very important, but the "WHY? TEST" is the surest way to properly identify the main conclusion if you have any doubt. That is because it is based on the true difference between a premise and a conclusion. The premise supports the conclusion, but not the other way around.

Now that we have the conclusion sorted out how about the question? Does anyone want to venture an answer?

The answer should be D IMO because it assumes correctly that the number of uncounted homeless vs the rich is same.

Answer is (B)

assuming that the census people are not having any other class of people in between rich and poor then the whole reasoning doesn't hold good

OA is C.

Sorry guys, I hate to say it but B and D are both wrong. I worked the problem and then confirmed it with some research. This is one of the 1000CR questions.

Here is how we can look at this one. As I mentioned above the conclusion is "The basic statistical portrait of the nation painted by the census is accurate." And the evidence is "some of the poor go uncounted, particularly the homeless; but some of the rich go uncounted as well"

So what they are assuming here is that these things are balanced. In other words a few rich people are not counted because they are traveling or something (this is really quite bogus. Rich people ARE ALWAYS COUNTED. The census is not a one-day process and the census is required by law to put down a number of people for every structure. Now rich people usually live in small numbers in large houses so they will be counted).

Now lots of poor people are not counted because they are homeless or lots of people are living in one house or for some other reason.

The only way that the conclusion is true "the basic statistical portrait of the nation painted by the census is accurate" is if the undercount of the rich people balances out the undercount of the poor people.

This is what choice C is saying. If the percentage of people not counted is the same in each category then have an accurate picture, even though we do not have an accurate count. Let me provide an analogy - say I am looking for the ratio of cats to dogs in my neighborhood. If there are 500 cats but I miss 100 of them and there are 200 dogs but I miss 40 of them then I still have an accurate picture. 500:200 is the same ratio as 100:40.

Now Choice B I can eliminate pretty quickly. The word "all" is tough thing to justify in an assumption answer. It is rare that you are ever assuming "all" of anything. If you can dunk a basketball does that rely on the assumption that ALL people can dunk? It does not.

B is also wrong because it does not harm this conclusion if not everyone is either poor or rich. If there are middle class people perhaps they are all counted. Let's say that many people are not poor and are not rich, in order for this to harm the conclusion we must assume that some of these people are not counted. This assumption requires its own assumption!! Not good.

Choice D exhibits two classic tricks. First is the percentage versus actual number trick - that I call verbal math. Choice C - the correct answer - talks about percentages. Choice D says the "number of homeless equals the number of rich" we are not really worried about the number of poor and rich that are not counted, but the percentage. If there are 10 times as many poor as there are rich in America - this is probably true - then having the same number of rich not counted would mean that they were WAY undercounted. Watch out for number versus percentage on the test.

However, D DOES NOT EVEN SAY NUMBER UNCOUNTED it just says "the number of homeless Americans is approximately equal to the number of rich Americans." Now this does not have to be true in order for the census to be accurate. The uncounted people just have to balance out. D is definitely wrong on this count.

Finally, D only talks about homeless, we are talking about all of the poor that are uncounted, homeless being the group most likely to go uncounted, but not necessarily the largest number of poor people that are uncounted.

A and E can be eliminated because they talk about motivations and that is not the essence of this argument.

Hope it helps!