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A chemical comp claims that, since only one of 520 rats that were give

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A chemical comp claims that, since only one of 520 rats that were give  [#permalink]

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New post Updated on: 07 Nov 2018, 05:36
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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(520?).

(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.

Originally posted by blog on 23 Jan 2008, 22:12.
Last edited by Bunuel on 07 Nov 2018, 05:36, edited 1 time in total.
Renamed the topic and edited the question.
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Re: A chemical comp claims that, since only one of 520 rats that were give  [#permalink]

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New post 25 Mar 2009, 09:01
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jainu - you're reading far too much into answer D. It says that *certain* (i.e. 'some', not 'all') substances which are carcinogenic for humans are not carcinogenic for rats. That means that some substances which are carcinogenic for humans *are* also carcinogenic for rats. In any case, if there were no relationship between rats and humans, the study in the passage would be completely pointless, and wouldn't prove anything about whether the sweetener was dangerous for humans, so D would weaken the argument.

The answer should be B - if 1 in 540 rats will develop cancer spontaneously, statistically you'd expect one of the rats in the study to develop cancer whether given the sweetener or not. This suggests that the sweetener may not have caused a single case of cancer, strengthening the claim that the sweetener is "not carcinogenic". If we didn't have this information, and if the one cancer from the study were indeed attributable to the sweetener, then clearly the sweetener *is* carcinogenic, at least in a small proportion of cases. For the company to make the rather extreme claim that the sweetener is "not carcinogenic", it must be able to establish that the sweetener is not responsible for a single case of cancer, so we need an answer choice which provides an alternative explanation for the one observed case of cancer in the study.
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Re: A chemical comp claims that, since only one of 520 rats that were give  [#permalink]

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New post 24 Jan 2008, 03:42
Conclusion here is that the sweetner will not cause cancer in humans since only 1/520 rats got cancer in a trial on 520 rats. The questions asks what will support this.

blog wrote:
A chemical comp claims that, since only one of 520 rats that were given high doses of a new artificial sweetner developed cancer while all the others remained healthy, the sweetner is not carcinogenic for human beings and ought to be approved for consumption 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 uaually also carcinogenic for other animals, such as guinea pigs, used in experiments. irrelevant
(B)The spontaneous incidence of cancer in this particular strain of rat is approx one in 540. lets see, so without any sweetner, a normal rat has 1/540 chance of getting cancer. So it can be assumed that the 1 rat that did get cancer in the trial did not get it because of sweetner, since 1/520 is approx. the normal rate anyways. So this proves that the sweetner is A-OK for humans
(C)Tests conducted on a certain strain of mouse show that, of 500 mice given a dose of sweetner similar to that of rats, 53 developed cancer. weakens the conclusion, in some ways. so we can eliminate
(D)Certan chemicals that are carcinogenic for human beings have been shown not to be carcinogenic for rats. weakens the conclusion. So this is eliminated since we are asked for something that strongly supports the conclusion.
(E)The average lifespan of the strain of rat used in the experiment when the rats wrer 13 months old. strain of rats? i think its a typo here.
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Re: A chemical comp claims that, since only one of 520 rats that were give  [#permalink]

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New post 24 Jan 2008, 05:35
B

A chemical comp claims that, since only one of 520 rats that were given high doses of a new artificial sweetner developed cancer while all the others remained healthy, the sweetner is not carcinogenic for human beings and ought to be approved for consumption for human consumption.

Which of the following, if true, most strongly supports the chemical company's claim?

the first assumption: one of 520 is not carcinogenic.
the second assumption: not carcinogenic for rats means not carcinogenic for human.


(A)Chemicals that are carcinogenic for rats are usually also carcinogenic for other animals, such as guinea pigs, used in experiments.
irrelevant.Two flaws: "animals" instead of "human", "carcinogenic" instead of "not carcinogenic".

(B)The spontaneous incidence of cancer in this particular strain of rat is approx one in 540.
it is the first assumption.

(C)Tests conducted on a certain strain of mouse show that, of 500 mice given a dose of sweetner similar to that of rats, 53 developed cancer.
irrelevant. Is 53 of 500 normal?

(D)Certan chemicals that are carcinogenic for human beings have been shown not to be carcinogenic for rats.
weaken

(E)The average lifespan of the strain of rat used in the experiment when the rats wrer 13 months old.
irrelevant.
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Re: A chemical comp claims that, since only one of 520 rats that were give  [#permalink]

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New post 22 Mar 2009, 00:01
i think D because if it is proved that chemicals carcinogenic for humans are not carcinogenic for rats. This means that carcinogens for humans are exclusive to carcinogens for rats. That is there is no common chemical that can be carcinogenic for both. Hence chemicals that have been found in arg to be carcinogenic for rats are not carcinogenic for humans. Hence can be approved.
Also,
If carcogenic for humans ---> not carcogenic for rats
reverse the relation....Carcogenic for rats -----> not carcogenic for humans.So clealry D

So D
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Re: A chemical comp claims that, since only one of 520 rats that were give  [#permalink]

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New post 23 Apr 2018, 07:55
If naturally 1 out of 540 mice get this , then 1 mice that got cancer in studies was not because of sweetener but natural cause. that is what given at B.
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Re: A chemical comp claims that, since only one of 520 rats that were give  [#permalink]

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New post 28 Mar 2019, 12:37
(B)The spontaneous incidence of cancer in this particular strain of rat is approx one in 540.
it is the first assumption.

Even in the increased sample size of rats, there is still just 1 rat who got Cancer, this proves the point that the rat has caught cancer for some other reason than sweetner. Hence B is correct.

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Re: A chemical comp claims that, since only one of 520 rats that were give   [#permalink] 28 Mar 2019, 12:37
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A chemical comp claims that, since only one of 520 rats that were give

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