A nutritionist studying the effects of massive doses of vitamin C foun

Question

A nutritionist studying the effects of massive doses of vitamin C found that of a group of 600 people who regularly took 1,500 mg of vitamin C daily for a year, fewer than 9 percent suffered serious cases of flu; of a group of 600 people who took 250 mg of vitamin C (the standard recommended daily allowance) daily for a year, 34 percent suffered at least one serious case of flu; and of a group of 600 people who took no vitamin C for a year (other than that found in the foods in a balanced diet), 32 percent suffered at least one serious case of flu.

Which of the following hypotheses is best supported by the evidence above?

(A) The effectiveness of vitamin C in preventing serious cases of flu increases in direct proportion to the amount of vitamin C taken.

(B) Vitamin C is helpful in preventing disease.

(C) Doses of vitamin C that exceed the standard recommended daily allowance by 500 percent will reduce the incidence of serious cases of flu by 25 percent.

(D) Massive doses of vitamin C can help to prevent serious case of flu.

(E) A balanced diet contains less than 250 mg of vitamin C.

KarishmaB · Accepted Answer

Quite a bit of confusion on this one... let's see if we can sort it out.

Read the question stem: Which of the following hypotheses is best supported by the evidence above?

The use of the word 'Hypotheses' signifies that what we are looking for is a proposition that is highly probable in the light of the data given in stimulus. 
The stimulus provides evidence (premises) for one of the answer options. So that answer option must be a hypothesis that is supported by the stimulus.

Premises:
- massive doses of vitamin C found that of a group of 600 people who regularly took 1,500 mg of vitamin C daily for a year, fewer than 9 percent suffered serious cases of flu; 
- of a group of 600 people who took 250 mg of vitamin C (the standard recommended daily allowance) daily for a year, 34 percent suffered at least one serious case of flu; 
- of a group of 600 people who took no vitamin C for a year (other than that found in the foods in a balanced diet), 32 percent suffered at least one serious case of flu.

Let's look at the options to see which one is supported by this data.

(A) The effectiveness of vitamin C in preventing serious cases of flu increases in direct proportion to the amount of vitamin C taken. 
Not supported by the study. We do not know how much vitamin C was taken by people who took a balanced diet only. Anyway, we cannot establish the direct proportion.

(B) Vitamin C is helpful in preventing disease. 
Too generic. Talks of disease in general. Not supported by the study.

(C) Doses of vitamin C that exceed the standard recommended daily allowance by 500 percent will reduce the incidence of serious cases of flu by 25 percent. 
The popular but incorrect option.  There is a difference between 'by 25%' and 'by 25 percent points'.  If incidence of serious cases of flu was 34% and it reduces to 9%, that is a reduction of (34-9)/34 = 73.5% in the incidence. Or I can say that the incidence of serious flu has reduced by 25 percent points. 
Similarly from 5%, if the growth rate goes up to 6%, that is an increase of 1/5 *100 = 20% (not 1%)
But I can say that the growth rate has increased by 1 percent point.

(D) Massive doses of vitamin C can help to prevent serious case of flu. 
This is the hypothesis that is best supported by the study. Please note that it is not a 'must be true' statement. The author has already mentioned that these are hypotheses. We need to pick the one that is best supported by the stimulus. It is clear what massive doses are since the premise mentions "studying the effects of massive doses of vitamin C found that of a group...". The results of the study imply that massive doses of vitamin C can help prevent serious case of flu.

(E) A balanced diet contains less than 250 mg of vitamin C. 
No information about this. If anything, in the group taking a balanced diet, the incidence of serious flu was slightly less than those taking 250 mg. So if we do want to infer something, we might be tempted to infer (wrongly, let me add) that a balanced diet has more than 250 mg of Vitamin C. We also don't know what kind of diet was taken by people taking 250 mg of Vitamin C.

Answer (D).

walker · Answer

D

A nutritionist studying the effects of massive doses of vitamin C found that of a group of 600 people who regularly took 1,500 mg of vitamin C daily for a year, fewer than 9 percent suffered serious cases of flu; of a group of 600 people who took 250 mg of vitamin C (the standard recommended daily allowance) daily for a year, 34 percent suffered at least one serious case of flu; and of a group of 600 people who took no vitamin C for a year (other than that found in the foods in a balanced diet), 32 percent suffered at least one serious case of flu.

Which of the following hypotheses is best supported by the evidence above?

(A) The effectiveness of vitamin C in preventing serious cases of flu increases in  direct proportion  to the amount of vitamin C taken. -  irrelevant 
(B) Vitamin C is helpful in preventing disease. -  it is not correct. Non-massive doses are not helpful. "Massive doses of vitamin C are helpful in preventing disease" would be better. 
(C) Doses of vitamin C that exceed the standard recommended daily allowance by 500 percent will reduce the incidence of serious cases of flu by 25 percent. -  25% is wrong and it is an strange hypothesis: what about 24%? or 24,8%? Also we have not precise data here: "suffered at least one" vs. "non-suffered" in the passage and "the number of cases" in this hypothesis. 
(D) Massive doses of vitamin C can help to prevent serious case of flu. -  the best. "Massive" sounds good because it comes form the passage: "A nutritionist studying the effects of  massive  doses of vitamin C..." 
(E) A balanced diet contains less than 250 mg of vitamin C. -  we cannot conclude it from the passage. In the passage 1500mg. 250mg are "extra" doses of vitamin C rather than "total" ones.

hanumayamma · Answer

Given:
1. 600 people 1500mg < 9%
2. 600 people 250mg 34 %
3. 600 people diet 32%

(A) The effectiveness of vitamin C in preventing serious cases of flu increases in direct proportion to the amount of vitamin C taken. ( Not really – from 2 and 1, it is not proportion – eliminate it )

(B) Vitamin C is helpful in preventing disease. ( Yes, but only flu is mentioned as part of the argument – eliminate it )

(C) Doses of vitamin C that exceed the standard recommended daily allowance by 500 percent will reduce the incidence of serious cases of flu by 25 percent. ( Will reduce – conclusion, but for hypothesis, this is extreme – eliminate it )

(D) Massive doses of vitamin C can help to prevent serious case of flu.( From 1 it is clear – hold it )

(E) A balanced diet contains less than 250 mg of vitamin C. ( May be true – but that’s not what the passage about – eliminate it )

Answer: D

vaibhavtripathi · Answer

IMO D..

"...by 500 percent   will   reduce the incidence of serious..."

I rejected C because "will" made it too strong to be a hypothesis...

gmat1011 · Answer

According to the websters dictionary "hypothesis" can mean one of 3 things. One of the listed meanings is: an assumption

When the GMAT uses the word "hypothesis" does it require the use of the "must be true" test associated with an assumption or even a conclusion or a simple can be true/likely standard used for strengthen/weaken questions?

Posted from my mobile device

KarishmaB · Answer

Though the choice of 'can' definitely makes more sense when putting forward a hypothesis, I still may not reject a choice solely on the basis of the use of 'will'. I can definitely formulate a conditional proposition such as:
If A happens, B will happen. - Here A is my hypothesis but the proposition is using 'will'.

KarishmaB · Answer

Hypothesis means it is not an established fact. It is either used as 'working hypothesis' where it is a guess to guide further investigation or it is something highly probable in light of evidence provided. The second meaning is the way the word has been used here.

When the dictionary says that a hypothesis could be a mere assumption too, it means something that is not established to be true. Something that is just being assumed for some purpose. When we use 'assumption' in our CR questions as in 'which of the following is an assumption in the argument?', we mean that the argument was given by assuming something.  That assumption was taken to be true to arrive at the conclusion.  That is why we check for 'must be true' with respect to the conclusion.

Conclusion is what you can infer without doubt. If the given premises are true, it must be true. 
You can see a question that says "Which of the following can be concluded from the argument above?"
But you will not see "Which of the following hypothesis can be concluded from the argument above?" It will be "Which of the following hypothesis is  best supported  by the argument above?"

Azakura16 · Answer

A nutritionist is studying the effects of vitamin C and finds the following:
Group 1: In a group of 600 people who regularly took 1,500 mg of vitamin C daily for a year, fewer than 9% suffered a serious case of the flu.
Group 2: In a group of 600 people who took 250 mg of vitamin C (the standard recommended daily allowance) daily for a year, 34% suffered at least one serious case of the flu.
Group 3: In a group of 600 people who took no vitamin C supplements in addition to the amount of vitamin C found in their balanced diet, 32% suffered at least one serious case of the flu.

We’re looking for an inference that can be made from these observations.

A. This isn’t supported, because the people who supplemented 250 mg daily had a slightly higher rate of serious flu cases than those who did not supplement vitamin C at all.
B. This isn’t supported either, because the 250 mg group was still a little higher than the 0 mg group.
C. This is an overstatement. We don’t know that doses of 1500 will certainly reduce the incidence of serious flu cases by 25%. The observations were only based on 1800 total participants, so they don’t necessarily hold true for everyone in the world.
D. This is supported, because of the phrasing. Massive doses of Vitamin C  can  help to prevent serious flu cases. The group that took the largest doses did have a much lower rate of serious flu cases.
E. We don’t have enough information about the balanced diet to infer this. For all we know, every group was on the same balanced diet.
Best answer is D.

A nutritionist studying the effects of massive doses of vitamin C foun

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