#7 - Concept Reference, Parallel

[Administrator]

Complete Question Explanation

The correct answer choice is (E).

Answer choice (A):

Answer choice (B):

Answer choice (C):

Answer choice (D):

Answer choice (E): This is the correct answer choice.

This explanation is still in progress. Please post any questions below!

[LSAT99.9]

Hello,

I am confused as to why E is the correct answer. From my understanding, El Niño can be seen to mask or mimic the actual effects of eruptions. However, wouldn't A) the weight of a package affect the actual weight of the contents of a package as (weight of package as whole - weight of packing material = actual weight of contents) , which is similar to (overall volcano climax connection - effects of el-Nino = actual effects if eruptions)? Wouldn't C the magnification of the lens also skew the ACTUAL size of object?

I know something in my reasoning here is flawed. Please help! Why is E the right answer?

Thank you so much!

[Emily Haney-Caron]

Hi LSAT99.9,

Thanks for the question! This is definitely a tricky one. Here, the author of the passage is focused on identifying the true cause of a change (in that case, change in temperature). E is similarly concerned with understanding the source of a particular change. E and the example in the passage both fail to account for one partial explanation in trying to identify the impact of another explanation on a particular phenomenon. A and C, on the other hand, are not focused on identifying a change; C also does not mention multiple causes, which will be necessary for the correct answer.

[mN2mmvf]

Hi,

Can you help me understand why (D) is incorrect? I read the question to mean El Nino introduced a bias into the study, which Mass and Portman tried to remove. (The bias could go in either direction, either making the cooling brought about by an eruption, or mimicking the cooling.)

I read D to mean that the false crime reports would introduce a bias into the study, and thus similarly had to be weeded out.

The other choice I considered was (E), but I didn't quite understand what bias would be eliminated in a population count by considering the *age* of new immigrants. I understand why you need to account for new immigration before attributing a population change to new births alone, but what difference does the age of the immigrants make? That's why I'd wanted to eliminate (E).

Thanks!

[Jonathan Evans]

Hi, mN2,

Great question on a difficult problem!

We need to sort out what to parallel between the circumstances outlined in the stimulus and the answer choices here. Let's pick out the salient features from the passage:

• Data derived from series of annual events.
• Several disparate data points contribute to overall average.
• Not accounting for one of these data points distorts overall result.
• Each datum is itself a valid part of the overall picture.

This last point is what distinguishes (D) from (E). In (D), we have an issue with counting "fake" crime along with real crime statistics. Fake crime has no place in such statistics and, in addition to distorting the average, needs to be discounted entirely.

In contrast, weather phenomena other than the volcanic ash do have an effect on weather. To discount other weather trends would be equally distorting. Therefore, far from being erroneous or fake data, this El Niño phenomenon is an integral part of the complete picture of weather trends.

I hope this helps!

[mN2mmvf]

Thanks. I think I understand what you're saying about (D) -- that it's entirely garbage data, instead of distortive but still partially helpful -- but why are the ages of immigrants in (E) not entirely irrelevant too?

[Adam Tyson]

The age of immigrants is relevant, mN2mmvf, because we are talking about the average age of a country's population. You have to account for the age of everyone alive in the country, and that includes the ones that arrived through immigration after the last time you checked the average! You also need to check the effect of people leaving the country. It's not just birth rates that affect a change in average age, but also the death rate and the rates at which people come in and go out.

Immigrants are people too! They need to be counted. That makes their ages relevant.

I hope that makes things a little clearer for you!

[mN2mmvf]

Hi Adam,

Maybe the question answer I have is misprinted on the PT copy I have. It talks only about not taking into account "the ages of new immigrants to a country before attributing a change in the average of the country’s population to a change in the number of births." Not "change in the average age of..."

That would explain my confusion if so!

[Adam Tyson]

That is indeed a typo, and it explains your confusion! Did we provide that copy?

[mN2mmvf]

No, I got it from a Kaplan collection. Sorry about that! But thank you!