CR prep question

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CR prep question

by jamesk486 » Tue May 22, 2007 1:30 pm
A birth is more like to be difficult when the mother is over the age of 40 than when she is younger. Regardless of the mother's age, a person whose birth was difficult is more likely to be ambidextrous than is a person whose birth was not difficult. Since other causes of ambidexterity are not related to the mother's age, there must be more ambidextrous people who were born to women over 40 than there are ambidextrous people who were born to younger women.




The argument is most vulnerable to which one of the following criticisms?

(A) It assumes what it sets out to establish

(B) It overlooks the possibility that fewer children are born to women over 40 than to women under 40

(C) It fails to specify what percentage of people in the population as a whole are ambidextrous

(D) It does not state how old a child must be before its handedness can be determined

(E) It neglects to explain how difficulties during birth can result in a child's ambidexterity
Source: — Critical Reasoning |

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by f2001290 » Wed May 23, 2007 3:39 am
I will go with B.

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by 800GMAT » Wed May 23, 2007 3:32 pm
My answer is E.

Reasoning Attempt:
If X comes after Y, then we can say that Y caused X only if we are able to explicitly show how Y caused X.

So, if difficult birth implies ambidexterity, then the author should also explain how is ambidexterity caused by difficult child birth. Else it will be a logical fallacy- causation vs correlation

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by ldoolitt » Wed May 23, 2007 3:33 pm
I concur. Its B

A) It doesn't assume what it set out to prove; that more ambedex. people are born to women over 40 than under 40.

C) It does fail to specify it but the conclusion does include the total sample space of people born (provided there are no people born to men).

D) Irrelavant to the argument.

E) It was not the purpose of the argument to explain WHY, only to give a correlation.

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by ldoolitt » Wed May 23, 2007 3:36 pm
800GMAT wrote:My answer is E.

Reasoning Attempt:
If X comes after Y, then we can say that Y caused X only if we are able to explicitly show how Y caused X.

So, if difficult birth implies ambidexterity, then the author should also explain how is ambidexterity caused by difficult child birth. Else it will be a logical fallacy- causation vs correlation
Good point, but its not saying that Y caused X (ie its not saying that difficult birth CAUSED ambidex) only that there is a correlation between difficult births and ambidex.

Edit: Note the question does have some ambiguity as it does mention causation in the conclusion sentence, however the conclusion is "there must be more ambidextrous people who were born to women over 40 than there are ambidextrous people who were born to younger women." not "difficult births cause ambidexterity."

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by 800GMAT » Mon May 28, 2007 10:57 pm
Oh I misread this question .....what is the OA?

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by pbanavara » Wed Oct 15, 2008 11:49 pm
It's B :

There are "more" ambidextrous babies born to women over 40 -> which fails to take into account the total number of babies born to women over 40.

So let's say:

20 babies were born to women over 40 and 50% were ambidextrous = 10
100 babies were born to women below 40 and 20% were ambidextrous = 20

which will refute the argument and hence will be a valid criticism.

-pradeep

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by khanshainur » Thu May 12, 2016 12:54 pm
I would go with option B as the correct option