大全-18-15

15.   Left-handed persons suffer more frequently than do right-handed persons from certain immune disorders, such as allergies. Left-handers tend to have an advantage over the right-handed majority, however, on tasks controlled by the right hemisphere of the brain, and mathematical reasoning is strongly under the influence of the right hemisphere in most people.

If the information above is true, it best supports which of the following hypotheses?

(A) Most people who suffer from allergies or other such immune disorders are left-handed rather than right-handed.

(B) Most left-handed mathematicians suffer from some kind of allergy.

(C) There are proportionally more left-handers among people whose ability to reason mathematically is above average than there are among people with poor mathematical reasoning ability.

(D) If a left-handed person suffers from an allergy, that person will probably be good at mathematics.（C）

(E) There are proportionally more people who suffer from immune disorders such as allergies than there are people who are left-handed or people whose mathematical reasoning ability is unusually good.

怎样排除A?

谢谢！

I see,3Q!!!

I think we may think this way.

if the number of left-handed people =the number of right-handed people, then A is right.

Since  left-handed persons suffer more frequently than do right-handed persons from certain immune disorders.  ( 10% for left-handed  and 5% for right-handed , for example. )

But it is not defined by the passage the percentage of  left-handed or right-handed people  among all people.  So A is not warranted.

proportion of l-h (left hand) good at math = a > proportion of r-h (right hand) good at math = b

a> (a*l-h)/(a*l-h+b+r-h) = a* (l-h/(l-h+b/a*r-h) = a* n (n<1) ==> c