M: It is almost impossible to find a person between the ages of 85 and 90 who primarily uses the left hand.Q: Seventy...

Ravi February 9, 2019

@Jessica-Killeen,

Happy to help!

Let's take a look at the argument before we look at the answer choices.

M tells us that it's nearly impossible to find a left-handed person
between the ages of 85 and 90.

Q replies by pointing out that 70 to 90 years ago, kids were punished
when they used their left hands and were forced to use their right
hands.

The question stem says, "Q's response serves to counter any use by M
of the evidence about 85 to 90-year-olds in support of which one of
the following hypotheses?"

This question is kind of tricky, but once we realize that it's
basically a cannot be true/must be false question, then it becomes
much easier to tackle. What type of conclusion would M attempt to make
that would not hold up based on Q's reply? Q's response gives us
evidence that older people and their propensity to be right-handed is
likely due to the environmental factors these people grew up with in
being forced to use their right hands, which is why so few of them are
lefties. This casts doubt on the possibility that the reason there are
so few 85 to 90-year-old lefties is due to genetics or some other
cause.

Now that we have an idea of what's going on, let's take a look at the answers.

You asked about (A) and (E). and are wanting to know how (A) is
correct and (E) is wrong, and you're confused as to how the stimulus
supports a hypothesis about survival when it doesn't discuss survival
at all.

Based on what you wrote, it sounds like you may have misinterpreted
what the stimulus is telling us to do.

The way the stimulus is worded, we're trying to pick an answer that,
if we take Q's response to be true, would prevent M's statement from
supporting something. The stimulus, with Q's response to M's
statement, DOES NOT support a hypothesis about survival, and this is
exactly why (A) is our answer.

(A) says, "Being born right-handed confers a survival advantage."

The reason this is the correct answer choice is because of M's
reference of the ages of the people who are almost all right-handed
(the 85 to 90-year-old group). Based on this evidence, it's reasonable
that somebody could conclude that being right-handed confers some sort
of survival advantage because such a high percentage of people 85 to
90 are right-handed and they're also all very old. However, when Q's
response enters, Q's evidence pertaining to how people of that
generation were raised and encouraged to be right-handed brings up a
strong counter to the conclusion that being right-handed confers a
survival advantage. If pretty much everyone in this age group was
forced to be a righty anyway, what's to say that THAT's not the cause
of there being such a high proportion of people 85 to 90 who are
right-handed?

(A) is a conclusion that, if we accept Q's response to M's statement,
must be false, so this is the correct answer.

(E) says, "Physical habits learned in school often persist in old age."

According to the information in the stimulus, this is a statement that
has to be true. If people 85 to 90 were almost all forced to use their
right hands, and if people in this age group now are almost all
right-handed, then it must be true that physical habits learned in
school often persist in old age. Remember, with this question, we're
looking for an answer choice that represents a statement that MUST BE
FALSE given Q's response to M's statement. Since (E) must be true
given the information we have in the stimulus, we can get rid of this
answer choice.

Does this help? Let us know if you have any more questions!