Critical Reasoning

Temperatures in the Pacific Northwest have risen steadily since 1981, averaging 2.07 degrees Fahrenheit warmer north of the 46th parallel than in the previous decade. Precipitation and water-table levels, which have historically maintained a measurable relationship to each other (within a scaled range of two to four points), have varied drastically from 1987 to 1991, sometimes deviating as much as six points in fewer than eight months. Reports from Canada indicate a similar median temperature increase, estimated at 2.02 degrees Fahrenheit; research from a 1992 study measures the relational swing in moisture levels at no more than three points.

Of the following, which conclusion is best supported by the evidence above?


The higher the temperature of a given area, the more likely it is that the water levels will vary.

The variation in temperature in the last decade has been less than the fluctuation of moisture.

When temperatures rise north of the 46th parallel, natural water exchange between land and atmosphere must change in the same proportion.

Within the last ten years, water table and precipitation levels have varied more in the Pacific Northwest than they have in Canada.

Canada will have more stability in weather than will the area of the United States above the 46th parallel.

In my opinion, the best answer is A.

The facts presented in the stimulus only allows us to figure out the general trend. The temperature to water correlations for the pacific northwest and Canada are not directly comparable. This effectively eliminates answers B through D.

I would go with D even tough A is almost as attractive as D is ..and also in tough questions the early options are more likely correct

It is a tough stem to digest within allotted time but D is based on the difference of the range of the changes so 2-4 VS 3



What is OA ?

OA is D only.

maihuna wrote:OA is D only.

I rock!

I almost spent 3 minutes or more to arrive at D - what's the source of this question please.

Source is prienston test for GMAT

the fact is, choice A tells usù

"The higher the temperature of a given area, the more likely it is that the water levels will vary. "

But the passage what is the temperature of the various areas BEFORE the swings.

It is a tough stem to digest within allotted time

logitech wrote:but D is based on the difference of the range of the changes so 2-4 VS 3

But how can u relate water table levels and precipitation with moisture unless mentioned. Pls explain

A mouthful of a stem! I can quickly eliminate A and C because they're trying to trick us into thinking there's some direct correlation. E is out because no one is discussing "stability of weather". I was left with B and D. I took out B because I didn't buy that comparison, and didn't have time to look at the stem again. D is actually true based on data provided. This is one of those questions you don't want to waste time trying to digest the stem.

In my opinion, the best answer is A, too