TOUGH KAPLAN CR QUESTION

varun007 · Posted: Sun Aug 31, 2008 12:40 am Post subject: TOUGH KAPLAN CR QUESTION

A chemical company claims that, since only one of 520 rats that were given high doses of a new artificial sweetener developed cancer while all the others remained healthy, the sweetener is not carcinogenic for human beings and ought to be approved for human consumption.
Which of the following, if true, most strongly supports the chemical company’s claim?
(A) Chemicals that are carcinogenic for rats are usually also carcinogenic for other animals, such as guinea pigs, used in experiments.
(B) The spontaneous incidence of cancer in this particular strain of rat is approximately one in 540.
(C) Tests conducted on a certain strain of mouse show that, of 500 mice given a dose of sweetener similar to that given the rats, 53 developed cancer.
(D) Certain chemicals that are carcinogenic for human beings have been shown not to be carcinogenic for rats.
(E) The average lifespan of the strain of rat used in the experiment is 2 years; the chemical company terminated the experiment when the rats were 13 months old.

OA IS B . CONFUSED . PLS CAN SOEBODY EXPLIAN IN DETAIL

sethids · Posted: Sun Aug 31, 2008 4:12 am Post subject:

The suitable answer choice would be the one which supports that the sweetner is safe for human consumption.
Because it has been tested on rats, if there is evidence that it is largely safe for rats, it should be more or less safe for other living species as well.

Choice B mentions that the rat species used in the experiment has a cancer incidence of 1 in 540 which is about 0.2% and hence is largely safe. It matches wich the premise in the question that only 1 of 520 rats developed cancer. So it was not by chance.

Looking at the other options:
A. Irrelevant.
C. Shows that 10% of rats developed cancer. It weakens the claim.
D. Doesn't support the claim.
E. Irrelevant.

gmatrant · Posted: Sun Aug 31, 2008 10:12 am Post subject:

but sethids..
where is the relation between the rats and the human beings... the claim is that the sweetner will not cause cancer to human beings. And the author is trying to prove that by using rats as a reference. But there should be a statement that if it is good for the rats it is good for the human beings too..

pls comment...

sethids · Posted: Sun Aug 31, 2008 12:54 pm Post subject:

The relation is the very nature of scientific experiments.
Any new medicine etc. are tested on laboratory animals first and then if they produce desired (or safe) results in those experiments then those are made available for human consumption.

James_83 · Posted: Sun Aug 31, 2008 5:16 pm Post subject:

sethids · Posted: Mon Sep 01, 2008 3:18 am Post subject:

Ok... Lets try to look at it this way...

The company claims that only one of 520 rats developed cancer when the new sweetner was tested on the rat species.

Now the choice B mentions that the species has a spontaneous cancer incidence rate of 1 in 540.
In this situation, even if the sweetner was not given to those rats, 1 in 540 has a chance of developing cancer.
According to the information provided, it is very much likely that it is the tendency of the rat species that led to the development of cancer and has nothing to do with the sweetner under test.

Hope that helps.

James_83 · Posted: Mon Sep 01, 2008 6:22 pm Post subject:

ohh....i got it...actually,i was taking this option into other way..

Thanks for explaination. Smile

NSNguyen · Posted: Sun Sep 07, 2008 12:18 am Post subject:

IMO: B
of all, only B confirm the result while others irrelevant or out of scope.