Logical Reasoning

PT103 · S3 · Q15 A person’s dietary consumption

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A person’s dietary consumption of cholesterol and fat is one of the most important factors determining the level of cholesterol in the person’s blood (serum cholesterol).

Statements

causal (one of the most important factors) How much cholesterol and fat we eat is a big causal factor when it comes to our serum cholesterol.

causal (rises proportionally to) For a while, the more cholesterol and fat we eat will cause our serum cholesterol to rise proportionally. But at a certain point, eating even tons more cholesterol and fat will barely increase our serum cholesterol.

mathematical (1/4) This threshold where it switches from rising proportionally to barely rising is 1/4 the consumption level of cholesterol and fat in today's average North American diet.

Evaluate

Our job on Inference (Must Be True / Most Supported) is to try to combine at least 2 of the facts we've learned.

The last two facts have an Overlapping Concept, "the threshold".

If the average North American diet is way above this threshold where serum cholesterol switches from rising proportionally to barely rising, then we can assume that the majority of North Americans are way above this threshold.

So we can plausibly infer that most North Americans don't have proportional responses to eating more/less cholesterol and fat; instead, they're on the side of the threshold where they will see only gradual rises in their serum cholesterol, no matter how much more cholesterol/fat they eat.

Goal

Look for the most provable answer (be wary of language that's too strong/specific, switches between Relative and Absolute, or brings in outside ideas).

It will probably be testing us on the idea that most North Americans aren't in that proportional range; they're in the range where their serum cholesterol changes only slightly even with dramatic increases in consumption.

15.

The statements above, if true, most strongly support which one of the following?

The threshold can be lowered
Out of Scope: lowering threshold
We have no evidence that the threshold can be raised or lowered. From the context, it seems like a fixed value.
8% picked this
People who consume an average
Opposite
The paragraph lets us know that if someone consumes an average North American diet, their serum cholesterol is 4 times the level of the threshold when it switches from proportional increases to barely increasing at all. People consuming an average North American diet will see their serum cholesterol levels rise only gradually, even with dramatic increases in consumption.
10% picked this
Correct
People who consume half as
Why this is right
People who are X will not necessarily be Y is very weak, provable wording, because you can prove such a claim with just one data point: someone who is X, but isn't Y Do we have reason to think that there's someone whose cholesterol and fat intake is 1/2 of the North American diet will not have half as high a serum cholesterol level? Yes! Let's say that the average consumption level of cholesterol and fat in a North American diet is 100 units. The threshold where our serum cholesterol switches from proportional increase to barely increasing is at 1/4 that consumption level, so 25 units. As someone goes from eating 1 unit of cholesterol and fat to eating 25 units, their serum cholesterol will rise proportionately. Since their consumption is 25 times as big, their serum cholesterol will be 25 times as high as it was. But now that they've crossed over that threshold, the serum cholesterol stops rising proportionately and begins barely rising at all. As someone goes from consuming 25 units of cholesterol and fat to consuming 100 units, their serum cholesterol will only gradually move up. Maybe it goes from 25 units to 30 units. This answer wants us to compare someone who eats 50 units of cholesterol/fat to someone who eats 100 (the average North American diet). Both of them are going to have around the same level of serum cholesterol. Maybe the 100 unit diet has a serum cholesterol level of 30 units, but the person eating 50 units will still have a serum cholesterol level of something between 25-30. To put more simply, since people eating the North American diet are at the stage where changes in consumption do not have proportional effects ... if they were to suddenly eat 1/2 as much cholesterol and fat (like the hypothetical person in this answer), they would not see their serum cholesterol drop proportionately.
Skill tested: Most Supported · how this choice captures the argument's function is the move to repeat next time.
80% picked this
Serum cholesterol levels cannot be
Too Strong: cannot be
The first sentence says that dietary consumption of fat and cholesterol is one of the most important factors determining serum cholesterol, but this answer choice is acting like it said that dietary consumption is the only factor.
1% picked this
People who consume less cholesterol
Opposite
If you're below the threshold, then you can easily reduce your serum cholesterol levels, because that's where consumption and serum cholesterol move proportionately. Someone who consumes less than the threshold could reduce their fat and cholesterol consumption by 10% and that would reduce their serum cholesterol by 10%.
1% picked this

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