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#25 - Despite a steady decrease in the average number of

LSAT2018
LSAT Master
 
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I understand the correct answer (B) and was able to choose it through POE. But on a side note, I would like to ask about the numbers and percentages concepts included in the stimulus. The stimulus begins comparing the percentages of two groups, and then uses this to make a conclusion on the number of television viewing and newspaper reading. Isn't this wrong in itself? Would it be possible to get an explanation on the numbers and percentages concepts here?
Adam Tyson
PowerScore Staff
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You're right, up to a point, LSAT2018. The argument here never does get around to saying anything about numbers, though, but only about changes in proportions. That is, the argument never gives any premises or conclusions about how many people do one thing or the other, but only that as one thing decreased dramatically, the other increased just as dramatically. That is evidence about an inverse proportion - one thing going up as the other goes down. That's also called a negative correlation.

From this correlation evidence, the author improperly draws a causal conclusion, and that's the flaw. Correlation, even negative correlation, never proves causation! To weaken the causal claim we might suggest an alternate cause for the correlation, or show that the correlation is not perfect in some way (sometimes one thing stays the same while the other changes, or sometimes they move in the same direction), or suggest that the supposed cause and effect are backwards, or raise doubts about the reliability of any data on which the author based his argument.

No need to delve into specific numbers here, since none were provided and none are really needed. It doesn't matter if newspaper readers went from 80% to 20% or from 60% to 40%. All that matters is that as newspaper reading went down, tv watching went up at about the same rate.
Adam M. Tyson
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