drewgr
can somebody further explain the correct answer please?
I'll give it a swing. I'll go through the problem (for the first time) and let you know what I do/think at each step. I don't know what the right answer is.
So I read the question first, then I deconstruct the argument:
Quote:
In a certain wildlife park, park rangers are able to track the movements of many rhinoceroses because those animals wear radio collars. When, as often happens, a collar slips off, it is put back on. Putting a collar on a rhinoceros involves immobilizing the animal by shooting it with a tranquilizer dart. Female rhinoceroses that have been frequently recollared have significantly lower fertility rates than uncollared females. Probably, therefore, some substance in the tranquilizer inhibits fertility.
Which of the following is an assumption on which the argument depends?
So it's an ASSUMPTION question. I know I'm looking for what MUST be true for the argument to hold.
So this argument CONCLUDES: "The tranq inhibits fertility"
The PREMISE(s): "Rhinos that have been tranqed a lot to get collars on have worse fertility."
So this is what I call a GUESSED CAUSE argument (almost every argument is either a PREDICTION/PLAN or a GUESSED CAUSE")
This arguments concludes that because they are tranqed a lot, and have fertility issues, the tranq must be *why*.
On Guessed Cause you're wondering two things: Is there ANOTHER cause for the effect (here, is there ANOTHER likely cause for the low fertility besides the tranquilizers?) Or is the cause REVERSED? (Maybe rhinos with low fertility are more likely to lose the collar for some reason?)
So I'm thinking an answer will show either that another likely cause ISN'T the reason for infertility, or that 'the causation is not reversed--low fertility doesn't lead to collars falling off and getting tranqued more.'
I go to my answers with these thoughts:
Quote:
(A) The dose of tranquilizer delivered by a tranquilizer dart is large enough to give the rangers putting collars on rhinoceroses a generous margin of safety.
(B) The fertility rate of uncollared female rhinoceroses in the park has been increasing in the past few decades.
(C) Any stress that female rhinoceroses may suffer as a result of being immobilized and handled has little or no negative effect on their fertility.
(D) The male rhinoceroses in the wildlife park do net lose their collars as often as the park's female rhinoceroses do.
(E) The tranquilizer used in immobilizing rhinoceroses is the same as the tranquilizer used in working with other large mammals.
C is the only thing that works for those goals.
Notice also that the conclusion is that a SUBSTANCE in the tranq is what causes the infertility. But C mentions another POSSIBLE CAUSE: stress caused from being immobilized and handed WHEN tranquilized. Animals that are tranquilized more are also IMMOBILIZED AND HANDLED more, and that causes stress that leads to infertility.
Hope that helps.
Here are some videos that will help develop the skills for this problem and ones like it:
THREE KEY QUESTIONS FOR CR:
https://www.youtube.com/watch?v=PfTcOr6zJjsTHE ASSUMPTION FAMILY:
https://www.youtube.com/watch?v=OITBw0ftwfoCRITICAL REASONING "GAMES":
https://www.youtube.com/watch?v=Xmz46ADcFdw