A recent study suggests that regular exercise improves the health

Hi MadaraU,

I agree with your point of view of looking at this question.

For Option D,
This is out of scope since it is too limited and narrow and only focuses on "strenuous exercise". In this case, we are assuming that any non-strenuous exercise would not result in reduced chances of getting a heart attack, which does not directly comprehend with the argument.

For Option B,
You cannot apply the negation test in this case since it is a Strengthening question. Remember, Negation test is only applied to assumption questions.
Now as you correctly stated in P2 and P3, the percentage of people getting a heart attack under the age of 60 has gone down from 50% to 40%. This means, that now (P3), people over the age of 60 account for 60% of the people getting a heart attack.
As option B states that the proportion of people over 60 has remained the same, yet 60% of them now account for getting a heart attack compared to 50% (5 years ago). Therefore, this directly strengthens the argument.

Using your numbers,
P2- 16 out of 33 people (50%) over the age of 60 were getting a heart attack 5 years ago.
The proportion has remained the same over 5 years.
P3 - 40 out of 66 people (60%) over the age of 60 get a heart attack.

B is the answer

Let me know if this makes sense or if you have any more questions.

gayatriv21 Paulli1982
The answer is B, as all other options are out of scope.
Please refer to the explanation I provided above to understand why Option B makes sense.

B is answer:

Let 5 years ago >60 yrs were 200 and <60 yrs were 100.
for eg 100 ppl get heart attache , 5 yr ago , 50 were under 60 and 50 were above 60. % of people getting heart attache under age of 60 is 50 getting HA/100 total nr under 60 *100 =50 and >60 will be (50/200) x100
again now for same 100 people who get heart attache 40 are under 60 and 60 are above 60. % getting HA under 60 = (40/100) *100 = 40 and > 60yrs % will be (60/200)*100
clearly under age of 60 hear attache are reduced by 10%. hence strenghtens

Main conclusion: regular exercise improves the health of person's heart and cardiovascular system.

Evidence: Five years ago, without regular exercise, people aged under 60 represented 50% of those who suffered from one or more heart attacks. Today, people under the age of 60 account for only 40% of the people who have suffered one or more heart attacks

Now, if the population size of the study participants varies, then we can no longer support the conclusion drawn. However, if we do have information that supports the idea that the participant population does not change over the course of 5 years, then we can reasonably support the link between "regular exercise" and the "results" claimed in the conclusion.

Only (B) talks about the population size.

(B) The proportion of the population aged 60 and over has remained constant over the last five years.

Hence, (B) is the right answer choice.

Hi experts,
Please help to explain reason why each choice is right or wrong. Thanks.

Pre-thinking:

Conclusion: Regular exercise improves the health of person's heart and cardiovascular system.

Premises on which it is based:

1) Five years ago, people under the age of 60 accounted for 50 percent of the people who had suffered one or more heart attacks.
2) Today, people under the age of 60 account for only 40 percent of the people who have suffered one or more heart attacks.
3) People under the age of 60 exercise more regularly today than they did 5 years ago.
4) Exercise habits of people aged 60 and over have remained the same.

Since we are asked to strengthen the argument, in such cause-effect questions, we are mainly looking for one of the following:

i) Ruling out an alternate explanation.
ii) Ruling out reverse causality.
iii) Ruling out confounding variable (correlation).

Let us examine the answer options:

A. Some people over the age of 60 exercise as much or more than do people under the age of 60. This does not impact our conclusion in any way since the time component is not addressed at all. Eliminate.

B. The proportion of the population aged 60 and over has remained constant over the last five years. This is a tempting answer. One alternate explanation for the change in heart attack rates could be that the population demographics have changed, with there being more people >60 today than five years ago. This option partially rules this out (ideally, we would have wanted the option to say that the proportion of >60 has not increased rather than remained constant, since even a reduction in >60 proportion would strengthen our conclusion). But this is attractive at this point. Hold on.

C. The use of cholesterol-lowering drugs has reduced the frequency of heart attacks among all age groups. We are looking for a comparison between the two age groups (<60 and >60) and this option does not provide any such information. Eliminate.

D. People aged 60 and over are generally less capable of strenuous exercise than are people under the age of 60. Same problem as (A) - this does not address the time factor at all. Eliminate.

E. A number of factors, such as nutrition and stress levels, affect the incidence of heart attacks. This neither addresses age groups nor time. Eliminate.

Hope this helps.

IMO the option B is an assumption.

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