#21 - In an experiment, some volunteers were assigned to

[Chandler H]

(E) makes perfect sense to me now, but under timed conditions I chose wrongly for this question due to the syntax of words in the stimulus:

Premise: Some volunteers did aerobic exercise, some were assigned to weight lifting

Premise: After three months, each performed an arduous math calculation.

Conclusion: aerobic exercise helps the body handle psychological stress

I fell for (A), trying the Negation technique: Three months is not enough time for the body to fully benefit from aerobic exercise.

After reviewing it I realize this answer was a trap and actually has no effect on the argument because the stimulus does not claim the participants did aerobic exercise for 3 months. The amount of time each group spent working out is actually not specified. It only states that a period of 3 months had passed, then they did the math calculation.

Hi mmjd12,

You might be missing a premise here! The diagram of the argument looks more like this:

P1: Some people did aerobic classes, and others did weight-training classes
P2: The people who did aerobics were less stressed by an arduous mathematical calculation than the people who did weight-training
Conclusion: Aerobic exercise helps handle psychological stress

In order for this conclusion to be true, however, we need to know that the volunteers who did aerobic CLASSES actually did a significant amount of aerobic EXERCISE—more than the volunteers who were more stressed. (After all, maybe the classes were only 15 minutes long!) Answer choice (E) provides that reassurance.

Answer choice (A) is wrong partially for the reason you stated—the stimulus tells us that the volunteers did the CLASSES for three months, but not necessarily exercise. However, it's also wrong because it focuses on the idea of "fully benefiting" from the exercise. Nowhere in the stimulus does it assert that these volunteers "fully" benefitted from aerobics—merely that it had some positive effect on their ability to handle stress.

Does that make sense?

[willwants170]

I understand why E is right but doesn't B weaken the argument if you negate it? I saw the other explanations for B, but during my PT, I thought if you negated it, it allows for the combination of aerobics and weights helping the body handle psychological stress. However, now that I think of it, even if the combination of aerobics and weights helping the body handle psychological stress, it still supports the conclusion because the conclusion never said onlyaerobics help body handle stress. Would this be right?

[Jeff Wren]

Hi will,

Your observation about the conclusion never claiming only aerobics helps hands stress is exactly right.

There may be many factors that can help a person handle stress, such as getting enough sleep, eating healthy, meditation, etc..

All we get in this study (if we negate Answer B) is one group who did aerobics and weight training versus another group who just did weight training. Since the group who did aerobics and weight training did better at handling stress, then the aerobics seem to be helping the body handle stress, even if other factors also help.