Self-study
Physician: In an experiment, 50 patients with chronic back pain were divided into two groups. █████ ███████ ████ ███████ ██ ███ █████ ██ ███ ██████ ███ █████ █████ ████████ ██ ██████████ ████ ██ ███ ████████ ██ ███ █████ ██████ ███ ████ ███ ██ ███ ██████ ██████ ████████ █ ███████████ █████████ ██ █████ ████ █████ ████ ████████ ██████ ███ ████████ █████████ ██ █████████ ████ ████ █████
Summarize Argument
The physician's conclusion is in the last sentence, marked by "this shows that": magnetic fields likely help alleviate some back pain. This is based on a study where more patients who had small magnets placed on their backs reported significant reductions in pain than patients who received no treatment.
Notable Assumptions
The physician's argument is based on patients' reports of pain reduction. But since the control group received no treatment at all--instead of, say, having small non-magnetic disks placed on their backs--it's possible there is a placebo effect at play. Simply receiving some kind of treatment might cause patients to report or feel less pain, regardless of whether that treatment actually has genuine pain-reducing qualities on its own. The physician assumes this is not the case, and that there is an actual connection between magnetic fields and reduced pain.
4.
Which one of the following, ██ █████ ███████████ ███ █████████ █████████ ███████ ██ ███ ███████████ █████████
a
A patient's merely ███████ ████ █ █████████ ███ ████ ███████ ███ ████ ██ ███████████ ██ ███ ██ ███ ██████████
This is an effective counter to the physician's argument. Magnets are a placebo. It's possible that if the other group had had some kind of \"treatment\" administered, they also would have reported less pain. Thus, the physician’s conclusion that magnets probably reduce back pain seems less likely.
Alternate explanation
Alternate explanation
Weaken: Introduce or support an alternate explanation for a phenomenon.
Strengthen: Helps to eliminate an alternate explanation for a phenomenon.
b
Most physicians believe ████ ██████████ ████████ ███████ ████ ████ ████ ███████████ ████ ███████ ███
This is irrelevant. The stimulus doesn't talk about medication versus magnets. We just want to know whether magnets can effectively relieve back pain or not--it doesn't matter if medication can do so even more effectively.
c
No other experiments ████ ████ ████ ███████ ████ ████████ ██████ ██████ ████ ██ ███ ████ █████ ████ ███ █████
This doesn't weaken the argument, which is only focused on back pain, not other types of pain. Notice also that \"no other experiments have been done\" is different from \"no other experiments have shown\". The second phrase would tell us that other experiments have been done, and potentially found results undermining the ones from the experiment in the stimulus. This might weaken the argunment. But if no other experiments have been done, this experiment could still be valid.
d
Some of the ██████████ ███ ██████ ██████ ███ ██████████ ████████ ████ ██████ ███ ██████████ ████ ████████ ██████ ███████ ████ █████ ███ ████ ████ ███ ████████ ████████ ██ ██████████ ███ ███████████
This is trying to suggest that the experiment was biased. But most scientists who have a hypothesis might be somewhat in favor or against it before starting an experiment, and if these scientists--notice that we don't know how many there were--didn't directly conduct the experiment, it's unclear how they could have compromised the results.
e
There was wide █████████ ██ ███ ████████ ██████ ██ ███ ███████ ████ ████ ████████ ██ ███ ████████ ██ ███ ███████████
Irrelevant. We don’t care what caused the pain in the first place. We care how well, if at all, the magnets relieved it.