Q17 - In deep temperate lakes

[mshinners]

Question Type:
Necessary Assumption

Stimulus Breakdown:
Trout like cold water. In dt lakes, the cold water is at the bottom in summer and the top in winter. The turnovers happen in fall and in late winter. So if an angler is fishing in late winter, they should focus on the shallows/near the surface.

Answer Anticipation:
The conclusion recommends focusing on water near the top, which we know is cold after the fall turnover but before the late winter turnover. These anglers want cold water since that's where the trout are.

So will this water be cold? Looking at the timeline, we see the turnover happens in late winter. If the turnover has happened, then the anglers should actually fish at the bottom of the lake. If it hasn't, then the argument works. The answer should state that the turnover hasn't yet happened.

Correct answer:
(E)

Answer choice analysis:
(A) Out of scope. The overall relative ease doesn't matter; the location of trout does.

(B) Out of scope. Density and heaviness don't matter since we already know where the cold/hot water is during the different times.

(C) Out of scope/degree. Other lakes don't matter since our premise and conclusion are both limited in scope to deep temperate lakes.

(D) Out of scope. Feeding habits could potentially be related to where the trout are hanging out, but the argument doesn't require it to be a factor since it establishes temperature as the determinant.

(E) Bingo. If we negate this and the turnover has occurred, the anglers should be trying to reach the colder water at the bottom of the lake.

Takeaway/Pattern:
Negation test. Always negate the answer you believe is correct to test it in a Necessary Assumption question.

#officialexplanation

[AnnaC659]

Question Type:
Necessary Assumption

Stimulus Breakdown:
Trout like cold water. In dt lakes, the cold water is at the bottom in summer and the top in winter. The turnovers happen in fall and in late winter. So if an angler is fishing in late winter, they should focus on the shallows/near the surface.

Answer Anticipation:
The conclusion recommends focusing on water near the top, which we know is cold after the fall turnover but before the late winter turnover. These anglers want cold water since that's where the trout are.

So will this water be cold? Looking at the timeline, we see the turnover happens in late winter. If the turnover has happened, then the anglers should actually fish at the bottom of the lake. If it hasn't, then the argument works. The answer should state that the turnover hasn't yet happened.

Correct answer:
(E)

Answer choice analysis:
(A) Out of scope. The overall relative ease doesn't matter; the location of trout does.

(B) Out of scope. Density and heaviness don't matter since we already know where the cold/hot water is during the different times.

(C) Out of scope/degree. Other lakes don't matter since our premise and conclusion are both limited in scope to deep temperate lakes.

(D) Out of scope. Feeding habits could potentially be related to where the trout are hanging out, but the argument doesn't require it to be a factor since it establishes temperature as the determinant.

(E) Bingo. If we negate this and the turnover has occurred, the anglers should be trying to reach the colder water at the bottom of the lake.

Takeaway/Pattern:
Negation test. Always negate the answer you believe is correct to test it in a Necessary Assumption question.

#officialexplanation

I had trouble quickly understanding this stimulus and was afraid I would be spending too much time on it. Now that I look back at it I see why E is the correct answer. But initially I thought answer choice A was correct because "the ease with which lake trout can be caught" referred to fishing at the right place/time (ie in shallow bay in winter). So when I negated the answer, I thought it destroyed the argument..

Could you help me understand better..?

Thank you in advance!

[ohthatpatrick]

(A) is an incredibly tough answer to me, because it seems like it could easily be inferred from the paragraph.

Given that the time of year affects the water temp and that the water temp affects where in the lake you'll find trout (and adding our own assumption that where the trout are located affects how hard/easy it is to catch them), you get the idea that the ease of catching trout is connected to time and water temp.

Of course, we ARE adding our own assumption that "WHERE the trout are found in the lake affects the ease with which lake trout can be caught".

Maybe that's not true, maybe as long as you know which part of the lake to fish in, it's always equally easy to fish for trout. If it's just as easy to fish at the top of the lake as it is at the bottom of the lake, then the ease of catching trout never really changes.

Perhaps (A) would be closer if it said "The ease with which lake trout can be caught by anglers varies with their knowledge of whether to fish at the top or the bottom of the lake".

Since the author is saying "anglers would DO BEST to aim for the surface rather than for the bottom", he is implying that there is something to be gained by aiming for the surface. And that "something to gain" sure seems like "an easier time catching trout".

But again, (A) is connecting two things that don't HAVE to be connected.
It would be better if it said,
"The location where lake trout can be most easily caught varies with the time of year and the water temperature"
or
"the ease of catching trout varies with an angler's knowledge of where the trout are located"

------------------------------

More to your overall process .... I think you need to be spending more time prephrasing an answer before you look at the choices.

Consider this argument and figure out what it's assuming:
"Pam can order one of two cookies. Cookie A is more satisfying for people who like salty cookies. Cookie B is more satisfying for people who like chocolatey cookies. So, if Pam plans to order the cookie that would most satisfy her, she would do best to get cookie A."

What is it assuming?
"Pam likes salty cookies more than she likes chocolatey cookies"

On this argument, we just needed to fill in the same blank:
"Trout are at the bottom of the lake in the summer, at the top of the lake in the winter. It switches in the fall and in late winter. So if you're going fishing in late winter ..... "

We should be stopping there and thinking, wait a sec ... what would be the advice for late winter?

Shoot, I'm not sure. Late winter is when it changes from fish on top to fish on bottom. But have we already changed or not?

" .... and there's still some ice on the water, aim for the top not the bottom".

Okay, I guess the author is assuming fish on top, so he's assuming we haven't changed yet.