丁丁倒数 61#

玛莎丁丁

In Yasukawa's month-long study of blackbirds, the percentage of smaller birds that survived the duration of the study exceeded the percentage of larger birds that survived. However, Yasukawa's conclusion that size is a determinant of a blackbird's chances of survival over a month-long period is probably mistaken, since smaller blackbirds are generally younger than larger ones.

The statements above, if true, support which one of the following inferences?

(A) Among the blackbirds that survived the month-long study, there was no relation between size and age.
(B) Larger blackbirds of a given age are actually more likely to survive over a one-month period than are smaller blackbirds of the same age,
(C) Among blackbirds of the same size, a difference in age probably does not indicate a difference in chances of survival over a one-month period.
(D) Among blackbirds of the same age, a difference in size may not indicate a difference in chances of survival over a month-long period.
(E) With a larger sample of blackbirds, the percentage of smaller birds that survive a one-month period would be the same as the percentage of larger birds that survive.

Which of the following if true, indicates that the criticism of Yasukawa's research is based on a misunderstanding of it?

(A) Yasukawa compared the survival chances of two different species of balckbirds, a larger and a smaller species, rather than of different sizes of birds within one species.
(B) Yasukawa examined blackbirds in their natural habitat rather than in captivity.
(C) Yasukawa did not compare the survival chances of blackbirds with those of other kinds of birds.
(D) Yasukawa noted that the larger blackbirds had more success in fights than did the smaller blackbirds.
(E) Yasukawa noted that the larger blackbirds tended to have more firmly established social hierarchies than did the smaller blackbirds.

玛莎丁丁

OA: D and A