Pharmacists recently conducted a study with respect to the reasons the

IMO A

I love this question type

We can guess the answer even before reading the options. The argument concludes that contact lenses cause dry eyes. How can we weaken this conclusion. This argument can be weakened in two ways:

1. If something else (not contact lenses) cause dry eyes
2. If dry eyes cause lead to wearing contact lenses.

Now lets see which option satisfies any of our two conditions:

It doesn't matters if this choice also addresses people who do not war lenses as long as it talks about possibility of a cause other than contact lenses which causes dry eyes. The statement identifies the possibility of a unknown cause which may be real underlying cause of both weak eyesight (people wearing lenses) and dry eyes.

Regarding B, B actually has 2 flaws which I mentioned in my previous statement. First the sentence itself is ambiguous and add to that the misleading word many.

'MANY' is a very misleading word, we generally think word 'many' represents a very large proportion of a group , but that is false.

Suppose in your college there are 100 students and 80 of them know how to speak in Japanese , you will say many people in my college can speak in Japanese. So here 'many' represents 80 % of the group. Now I can say in my town 200 people can speak in Japanese . 200 is definitely a number with which we can use 'many'. So I can say many people in my town can speak in japanese . But my town has 20 million people. so here 'many' represents just 200/20 million = 0.001 %. people of the group. That is why many is the one of the most misleading term . It simply doesn't clarifies an issue.

Not sure but I have seen so many instances where if the answer choice doesn't have the exact population/subject that was talked about in the subject it gets rejected as out of scope.

I think you are not connecting the subjects properly. The statement 1 only changes a few words but implies contact lenses.

An inherited condition can cause both weak eyesight and dry eyes.

The weak eyesight above subtly conveys the situation of wearing lenses. The statement will be more direct if author wrote. 'An inherited condition can cause both problem requiring wearing contact lenses and dry eyes. But to make question difficult author plays with the wording. Hope you also got the problem with b.

May be if the statement read : An inherited condition in people can cause dry eyes... but since this statement doesnt say anything we can be sure that the subjects are people who wear contact lenses and not general population or no one else... Not sure just a random thought that came to my mind. Not sure if i am correct here or no... Somehow I am not fully satisfied...

This statement identifies the possibility of 3rd agent causing the problem of both dry eyes and wearing lenses (weak eyesight) . For example

Ice cream sales increase in the summer. Violent crime also increases in the summer.
Therefore, ice cream causes violent crime.
-Assumes that correlation means causation. However, there is a third variable here -
the increased temperature in the summertime, which causes both ice cream sales
and violent crime to increase.

This is one of the repeated flaw patterns which question employs., Another right answer would have been a reason which suggested that dry eyes causes wearing contract lens or poor eyesight and not the other way. also you will always encounter subtler language the best way is to practise more.

No , I understand the logic of 3rd agent causing something and I dont deny that fact. The only thing here i am confused about is that if answer choice refers to the people who just wear contact lenses or everyone in this world(even who do not wear contacts) ... This is the part where my confusion lies thats all

what is important is that 'does explanation given in statement 1 includes the cases of people who wear the contact lenses or not'. the answer is yes we can attribute this 3rd unknown agent to be the cause of both dry eyes and weak eyesight (wearing lenses).

Now does this 3rd agent also works on people who do not wear eye lenses is not important for us (does this statement refer to other people too). it could also be a underlying agent which causes both wearing GLASSES and having dry eyes. So it can refer to even people who dont wear lenses (like to people who wear glasses) but the main issue of resolving the problems of contact lenses not causing dry eyes has been solved by this statement. Hope this helps.

vote for A

(weaken)
Conclusion: Contact lenses "by itself" causes dry eyes

Premise: Dry eyes more frequently --> who wore contact lenses than by customers who did not wear contact lenses.

(A) An inherited condition can cause both weak eyesight and dry eyes.
--> provide additional premise that states there are causes to dry eyes and not only the contact lenses. Weakens the conclusion.

(B) Physical exertion causes dry eyes in many people who wear contact lenses.
--> This strengthens the conclucion by stating that "dry eyes are caused by wearing contact lenses".what about the perople who dont wear contact lenses but still have dry eyes

(C) Most people who have dry eyes do not wear contact lenses.
--> But the premise in argument states otherwise (Premises should always be considered true, this information cannot be false)

(D) Most people who wear contact lenses do not have dry eyes.
--> But the premise in argument states otherwise (Premises should always be considered true, this information cannot be false)


(E) Both weak vision and dry eyes cause headaches.
--> Out of scope argument has nothing to do with headaches

Hi,

this is how I did it:

You are looking for a cause and an effect. This is basic stuff. What will undermine the conclusion: well that some other cause produces the exact same effect.

Now state the conclusion in simple terms: "Wearing contact lenses cause dry eyes"

Look at the answer choices:

(A) An inherited condition can cause both weak eyesight and dry eyes. correct
(B) Physical exertion causes dry eyes in many people who wear contact lenses. Not correct Irrelevant
(C) Most people who have dry eyes do not wear contact lenses. Not correct (trap)
(D) Most people who wear contact lenses do not have dry eyes. Not correct (trap)
(E) Both weak vision and dry eyes cause headaches Irrelevant Not correct

Only A undermines.

Now verify if it make sense:

"Wearing contact lenses cause dry eyes" ==> BUT An inherited condition can cause both weak eyesight and dry eyes ==> Therefore, Contact lenses might cause dry eyes as well as an inherited condition can.

hih

Pharmacists recently conducted a study with respect to the reasons their customers purchased eye drops to soothe eye dryness. Dry eyes were more frequently experienced by customers who wore contact lenses than by customers who did not wear contact lenses. The pharmacists concluded that wearing contact lenses, by itself, can cause contact wearers to have dry eyes.

Which one of the following statements, if true, most seriously undermines the pharmacists' conclusion?

what is the conclusion--- wearing contact lenses, by itself, can cause dry eyes.

(A) An inherited condition can cause both weak eyesight and dry eyes. does this undermine "wearing contact lenses, by itself, can cause dry eyes"--- NO. An inherited condition can cause both weak eyesight and dry eyes. BUT WEARING CONTACT LENSES, BY THOSE WHO DO NOT HAVE INHERITED CONDITION, CAN STILL CAUSE DRY EYES......
(B) Physical exertion causes dry eyes in many people who wear contact lenses. DOES " wearing contact lenses, by itself, cause dry eyes"... MAY NOT BE SO...IT IS ACTUALLY PHYSICAL EXERTION NOT "wearing contact lenses, by itself" THAT CAUSES dry eyes...... hence a BETTER ANSWER.....

Pharmacists recently conducted a study with respect to the reasons their customers purchased eye drops to soothe eye dryness. Dry eyes were more frequently experienced by customers who wore contact lenses than by customers who did not wear contact lenses. The pharmacists concluded that wearing contact lenses, by itself, can cause contact wearers to have dry eyes.

Which one of the following statements, if true, most seriously undermines the pharmacists' conclusion?

(A) An inherited condition can cause both weak eyesight and dry eyes.
Could be weak eyesight means they wear glass or ignore or having laser operated. No where weakens the conclusion
wearing contact lenses can cause contact wearers to have dry eyes.

(B) Physical exertion causes dry eyes in many people who wear contact lenses.
(C) Most people who have dry eyes do not wear contact lenses.
(D) Most people who wear contact lenses do not have dry eyes. ==> ANSWER
(E) Both weak vision and dry eyes cause headaches

Argument says dry eyes is experienced by people who wore contact lenses.
Lets say the entire dry eyes set is A and contact lenses set is B and normal glasses set is C and no eye sight is D
Set A and B overlaps and Set A and C and Set A and D could overlap
But chance that large unoverlapped set of B could exists

Means lets say
Dry eyes = 10
Contact lenses = 40
NOrmal glasses = 25
No eye sight = 35

Dry eyes coincides with contact lenses is 9 and is equvivalent to 1% of contact lenses.
so many people with contact lenses are not having dry eyes which is weakening the conclusion that contact lenses causes dry eyes and is clearly mentioned in D


answer should be D

A is alright. This is a typical GMAT-like option:
Conclusion: X causes Y.
Weakening statement: Z causes X and Y. (Thus X does not cause Y - just that they happen together because something else causes both of them).

It is very difficult to pose a solid reason to eliminate D - it is trap, yes - but why is it a trap?
Take a look at the conclusion carefully: Wearing contact lenses CAN cause contact wearers to have dry eyes.

The conclusion does not say Wearing contact lenses WILL cause contact wearers to have dry eyes. So even if most of the people who wear contact lenses do not have dry eye, that does not weaken the argument, because the argument does not claim that whoever wears or most of them who wear contact lenses WILL have dry eyes. It just implies that there is a chance that if someone wears contact lenses, he/ she will have dry eyes caused by wearing the lenses.

A is indeed the right answer.

I am still confused why B is wrong. Isn't it saying that physical exertion rather than contact lenses itself causes dryness.

Option B seems to indicate that the combination of physical exertion and the wearing of contact lenses causes dry eyes. Hence this option in a way strengthens the argument.

Can somebody explain why B is not stronger than A here in regard to undermining the conclusion?

Thanks in advance

Hi riteshgupta1

Isn't option A making a logical jump by assuming that only people with weak eyes can wear lenses.