GMATPrep2: teenagers and smoking

Question

Could anyone explain me why???????? Will greatly appreciate..

https://s59.radikal.ru/i163/0909/8f/d0992c9e6e32.jpg 
 https://i012.radikal.ru/0909/73/aa780549b0ef.jpg

OA  A

nitya34 · Answer

yes E-weakening--so OUT
D-uses "SOME"--hence OUT
C-"FEW" and not strengthening--OUT
B-out of scope(OOS)

gurpreet07 · Answer

E is clearly out of scope..the argument is talking about smoking not the intake of alcohol
C and D are also out of scope......
B mentions that the study did not distinguish b/w the participant who smoked occassionaly and those who were heavy smokers.......this is also out of scope since we are concerend with teenagers who didn't smoked but eventually started smoking, there is no concern of heavy smoking..

Now the right option A says that "Participants who were depressed at the start of the study were no likely to be smokers 
after one year than those who where not depressed....in other words it says that if people who were already depressed and quitted smoking after one year then the increase in number of cases of depression is due the teenagers who started smoking......

Thus strengthening the argument........

mikeCoolBoy · Answer

This is a cause --> effect problem. The author conclusion is that smoking causes depression.

You can diagram this smoking ----> depression

Now what would weaken the argument ? if the relationship is reversed depression ---> smoking the argument would be weakened.

Option A removes this possibility and therefore strengthens the argument.
This is a common well pattern in critical reasoning that repeats in a lot of problems.

You have here another problem, although is an assumption problem, with the same reasoning

researchers-and-low-level-immune-83107.html

chandru42 · Answer

Good Question and thanku for the explanantions 
Chose A right away

manojgmat · Answer

where is the question, cannot find... :-)

Practicegmat · Answer

One question here on (a) why the Participants who were depressed at the start of the study were compared with those who were not depressed? Am still confused

tuanquang269 · Answer

I didn't see any premise and stem in this question.

GMATPrep2: teenagers and smoking

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