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Critical Reasoning: Inference Questions

Caffeine is a chemical compound that stimulates the human central nervous system. Research into the effects of caffeine has been performed by a myriad of companies from different places around the world, and new evidence is published every few months. High caffeine intakes cause nervousness and insomnia in some subjects while drowsiness and repose are experienced by others. Furthermore, some people report a laxative effect while in others it can result in constipation.

Which of the following conclusions is most strongly supported by the information above?



We cannot assume that the research mentioned in the argument was conducted inaccurately. Contradicting results in subjects do not imply anything about the accuracy of the collection of those results.

Furthermore, we know nothing about the size of test groups used in all the experiments mentioned in the argument so we cannot come to any conclusions in that regard.



This conclusion contradicts the premise A. The fact that the symptoms may vary does not mean that the central nervous system in some people is not affected.



This answer choice jumps to an unsupported conclusion. Although the symptoms experienced by subjects vary, we cannot assume that the research is not useful in some way and that nothing can be learned from it.



This answer choice introduces additional information about addiction that is not mentioned by the argument. Look for a conclusion based on information found in the premises given.

Did you pick this answer choice because of your own general knowledge about caffeine?



The argument gives us the impression that caffeine affects people in very different ways. Therefore, forming a concrete judgment about symptoms caused by the substance is difficult.

Remember not to get involved in the content of the question. The GMAT does not test your knowledge, but rather the ability to analyze and apply logic to new information. Focus only on what is given in the question or argument.


Since there is not enough consistency with regards to results, research of such a chemical is not advantageous and should be discontinued.
The individuality of human subjects creates difficulty when attempting to form a definitive judgement about the symptoms of caffeine.
Caffeine does not affect the central nervous system in all people and, therefore, physiological symptoms can also vary.
Caffeine can act as an addictive substance causing unpleasant side effects and harm to the human body's basic functions.
To conduct more accurate research, examinations should be carried out on larger test groups.