GMAT Critical reasoning (3) Inference and others

P. 147

Conclusion: the use of mullein leaf tea to treat dry cough is not as safe as was once thought

Evidence: mullein root and seeds are belived to contain rotenone, a substance that causes Parkinson’s disease

Assumption: A compound contained in the roots and seeds of mullein plant must also be contained in its leaves.  (* scope shift signal)

p.149

1.Conclusion: The Herbed wellness should add caffeine into their new herbal product that treats headache.

Evidence: 58% of headache suffers was completely cured after dosing the caffeine.  

Assumption: In experiment,  more than half of success out of total study participants is regarded a proven evidence enough to apply the expriment into real world.

2.Conclusion: High blood level of vitamin D reduces the risk of cancer in humans.

Evidence: people who are not exposed to UV don’t be provided enough Vitamin D. People who live in high latitude, where UV exposure is minimal have shown a high rate of cancer.   

Assumption: the shortage of vitamin D is the factor of cancer breakdown. (*Mistaking correlation for causation)

*New 문제유형 : necessary condition & sufficiency condition

It is an historical fact that only under conditions of profound societal instability are great works of literature produced. (a statement of necessity and not sufficiency) During the first century B.C., Rome experienced almost constant civil war accompanied by social upheaval. It wasn't until the ascension of Nerva to the throne in 96 A.D. that the situation stabilized. Throughout the second century A.D., Rome experienced a century of uninterrupted peace and stability.

If all of the statements in the passage are true, then which of the following must also be true?

a.During the first century B.C., great works of literature were produced in Rome.

=>social instability is needed to produce great literature, but it does not guarantee great literature

 b.Roman art of the first century B.C. was superior to Roman art of the second century A.D.

c.During the second century A.D., no great works of literature were produced in Rome.

=>great literature certainly could not have been produced during the second century A.D., because the necessary condition, instability, was absent

 d.Historically, great works of literature can stir emotions that find their expression in political action.

 e.The first century A.D. was a time of decreased literary production in Rome.