Pls come a Titan or instructor, it's tough CR

[tracyyahoo]

Researchers took a group of teenagers who had never smoked and for one year tracked whether they took up smoking and how their mental health changed. Those who began smoking within a month of the study's start were four times as likely to be depressed at the study's end than those who did not begin smoking. Since nicotine in cigarettes changes brain chemistry, perhaps thereby affecting mood, it is likely that smoking contributes to depression in teenagers.

Which of the following, if true, most strengthens the argument?

A.
Participants who were depressed at the study's start were no more likely to be smokers at the study's end than those who were not depressed.

B.
Participants who began smoking within a month of the study's start were no more likely than those who began midway through to have quit smoking by the study's end.

C.
Few, if any, of the participants in the study were friends or relatives of other participants.

D.
Some participants entered and emerged from a period of depression within the year of the study.

E.
The researchers did not track use of alcohol by the teenagers.

I know C,D,E are irrelevant, why A not B??? Pls explain me????

[ratan_2009]

i think its A

[mundasingh123]

Researchers took a group of teenagers who had never smoked and for one year tracked whether they took up smoking and how their mental health changed. Those who began smoking within a month of the study's start were four times as likely to be depressed at the study's end than those who did not begin smoking. Since nicotine in cigarettes changes brain chemistry, perhaps thereby affecting mood, it is likely that smoking contributes to depression in teenagers.

Which of the following, if true, most strengthens the argument?

A.
Participants who were depressed at the study's start were no more likely to be smokers at the study's end than those who were not depressed.

B.
Participants who began smoking within a month of the study's start were no more likely than those who began midway through to have quit smoking by the study's end.

C.
Few, if any, of the participants in the study were friends or relatives of other participants.

D.
Some participants entered and emerged from a period of depression within the year of the study.

E.
The researchers did not track use of alcohol by the teenagers.

I know C,D,E are irrelevant, why A not B??? Pls explain me????

Hi Tracy ,
I suggest that you go through the causation chapter in the Powerscore Cr . According to it
a causation relationship X->Y could be weakened by showing
1)an alternate reason for Y
2)Y lead to X and not X lead to Y.The reverse is true .
3)
4)
5)
There 5 ways in which the causation could be weakened
Option A here follows Technique No. 2 .It strengthen the argument by precluding the chance of technique 2 happening . It says Y did not lead to X .It strengthens the conclusion by defending the conclusion .

[navami]

Researchers took a group of teenagers who had never smoked and for one year tracked whether they took up smoking and how their mental health changed. Those who began smoking within a month of the study's start were four times as likely to be depressed at the study's end than those who did not begin smoking. Since nicotine in cigarettes changes brain chemistry, perhaps thereby affecting mood, it is likely that smoking contributes to depression in teenagers.

Which of the following, if true, most strengthens the argument?

A.
Participants who were depressed at the study's start were no more likely to be smokers at the study's end than those who were not depressed.

B.
Participants who began smoking within a month of the study's start were no more likely than those who began midway through to have quit smoking by the study's end.

-------------

We have to strengthen the conclusion ...
CONCLUSION : it is likely that smoking contributes to depression in teenagers

now how can we negate the colclusion ?
we can do it if we prove that the depressed people pick up the habit of smoking... ---(1)
and Option A says that the face (1) that 'that the depressed people pick up the habit of smoking' is not true.

[theforrestgump]

Researchers took a group of teenagers who had never smoked and for one year tracked whether they took up smoking and how their mental health changed. Those who began smoking within a month of the study's start were four times as likely to be depressed at the study's end than those who did not begin smoking. Since nicotine in cigarettes changes brain chemistry, perhaps thereby affecting mood, it is likely that smoking contributes to depression in teenagers.

Which of the following, if true, most strengthens the argument?

A.
Participants who were depressed at the study's start were no more likely to be smokers at the study's end than those who were not depressed.

B.
Participants who began smoking within a month of the study's start were no more likely than those who began midway through to have quit smoking by the study's end.

-------------

We have to strengthen the conclusion ...
CONCLUSION : it is likely that smoking contributes to depression in teenagers

now how can we negate the colclusion ?
we can do it if we prove that the depressed people pick up the habit of smoking... ---(1)
and Option A says that the face (1) that 'that the depressed people pick up the habit of smoking' is not true.

Once again DO NOT apply the Negation Test for questions apart from Assumption questions....if you do not believe me, the following should help explain

https://gmatclub.com/forum/negate-test-96785.html

[Bigred2008]

It should be A

A.
Participants who were depressed at the study's start were no more likely to be smokers at the study's end than those who were not depressed.


If you take a look at an argument you need to figure out what the weakness is, in this case what if "Since nicotine in cigarettes changes brain chemistry, perhaps thereby affecting mood, it is likely that smoking contributes to depression in teenagers." Anything that can strengthen the bolded portion. In this case, it eliminates the idea that people who are already depressed start smoking, rather then smoking causes depression.

[sl750]

In choice B, it is talking about one group that is as likely as the other group to quit smoking. We are not interested in whether the group has an addiction problem or not. So, this does not strengthen the argument

Only A, which is a convoluted response is the correct answer. Choice C,D,E can be easily eliminated