#20 - A person with a type B lipid profile is at much

[Administrator]

Complete Question Explanation

Must Be True—#%. The correct answer choice is (E)

Here information is provided about an experiment in which volunteers were placed on a low-fat diet.
Those with a type B lipid profile have a higher risk for heart disease than those with type A, and the
type B volunteers lowered their cholesterol levels during the experiment. The type A volunteers, on
the other hand, experienced no benefits from the experiment, and 40 percent even became type B’s
(meaning that their risk of heart disease actually increased).

The stimulus is followed by a Must Be True question, so the correct answer choice can be confirmed
by the information provided in the stimulus.

Answer choice (A): Since the stimulus provides no information regarding the portion of volunteers
who saw some risk reduction, this choice fails the Fact Test, cannot be confirmed by the information
provided, and must be incorrect.

Answer choice (B): The author provides that the type B volunteers lowered their cholesterol levels,
but no information is provided to allow comparison of the cholesterol levels of the two groups.

Answer choice (C): We are provided with no information regarding any other aspects of the
volunteers’ lives, so this choice fails the Fact Test.

Answer choice (D): There is no specific explanation for the change in lipid profiles, and the
group that experienced the cholesterol level decrease (type B) was different from the group that
experienced changes in lipid profile (type A).

Answer choice (E): This is the correct answer choice. Since 40 percent of the type A volunteers
shifted to type B, thus increasing their risk for heart disease, we know that at least some volunteers
increased this risk. We might note in this case the somewhat counter intuitive link between lower fat
and higher risk.

[Tmills4]

Hello,

Reading this MBT question, I can understand why A-D are incorrect. I am having trouble understanding why answer choice E is correct. From the stimulus, we know that the "type B volunteers cholesterol levels dropped substantially" and we know the "type A volunteers showed no benefit", which I would interpret to mean their cholesterol levels did not decrease; they could have remained the same or increased but it isn't inherently clear... is it? We know "40% of A profiles switched to B, but I am looking at the fact test methodology and I need help with my discernment. Thanks!

~T

[Dave Killoran]

Hello,

Reading this MBT question, I can understand why A-D are incorrect. I am having trouble understanding why answer choice E is correct. From the stimulus, we know that the "type B volunteers cholesterol levels dropped substantially" and we know the "type A volunteers showed no benefit", which I would interpret to mean their cholesterol levels did not decrease; they could have remained the same or increased but it isn't inherently clear... is it? We know "40% of A profiles switched to B, but I am looking at the fact test methodology and I need help with my discernment. Thanks!

~T

Hi T,

Thanks for the question! In this problem, answer choice (E) is supported by the combination of different statements in the stimulus. First, we know that, "A person with a type B lipid profile is at much greater risk of heart disease than a person with a type A lipid profile." So, if you have a Type B profile, you have a much great risk. Second, we know that in the experiment, "The type A volunteers, however, showed no benefit from the diet, and 40 percent of them actually shifted to type B profiles." So, when they did this experiment, 40% of the Type A profiles actually switched to Type B. Well, according to our prior sentence, this means they then had a much greater risk of heart disease. That's exactly what answer choice (E) is talking about—the people in the study who switched over now have an increased heart attack risk.

Note how that for (E), the cholesterol is irrelevant; it doesn't tell us anything. But, it's an eye-catching idea within the stimulus because we know in the real world there's a lot of talk about cholesterol and heart disease. But we can't draw any conclusion here from the cholesterol because they gave us no useful information besides how it changed (or didn't). You can't then go and make a judgment about it from just that info.

Please let me know if that helps. Thanks!

[Tmills4]

Awesome,

This helped a ton!