Self-study
Toxicologist: Support A survey of oil-refinery workers who work with MBTE, an ingredient currently used in some smog-reducing gasolines, found an alarming incidence of complaints about headaches, fatigue, and shortness of breath. █████ ████████ ██████████ ████ ████ ████ ██ ██████ █████ ██ ███ ██████ ██ █████████ █████████ ██ ██████████ ████████ ███ █████████ ██ ███████
Summarize Argument
The toxicologist concludes that cases of headaches, fatigue, and shortness of breath will soon increase. This is because gas with MBTE will soon be widely used, and people who work with MBTE report high rates of the aforementioned symptoms.
Notable Assumptions
The toxicologist assumes that the oil refinery workers' symptoms were caused by MBTE, and not by some other substance they worked with, such as the gasoline itself. The toxicologist also assumes that MBTE will be present in gasoline in sufficient quantities, or in such a way, as to cause the same symptoms in ordinary people that MBTE causes in refinery workers who work with it directly.
5.
Each of the following, if █████ ███████████ ███ ██████████████ ████████ ███████
a
Most oil-refinery workers ███ ██ ███ ████ ████ ████ ██ ███ ████ ███████ ██████ ████████ █████████ ██████████ ████████ ███ █████████ ██ ███████
This tells us that the symptoms experienced by these workers are likely caused by MBTE and not by something else that would affect all oil-refinery workers, like the gasoline itself. By ruling out an alternate explanation, this choice strengthens the toxicologist's argument.
Plausibility
Plausibility
Presenting evidence that corroborates (in Strengthen) or conflicts (in Weaken) with the author's hypothesized explanation or the predictions that follow from that explanation.
b
Headaches, fatigue, and █████████ ██ ██████ ███ █████ ███ ████████ ██ ███████ ███████ ██████████ ████ ███ ███████████ ███████ ███████ ██ ██████ ███████
This doesn't strengthen the argument. Knowing about other medical conditions that can lead to the same symptoms doesn't help us determine whether those symptoms will increase because of gasoline containing MBTE.
Directionally wrong
Directionally wrong
Answers that, if they have any effect, do the opposite of what we want (weaken when we're trying to strengthen, or strengthen when we're trying to weaken).
c
Since the time ████ ████████ ██████████ ████ ███ █████ ██████████ ██ █ ███ ████████████ ██████ █████ █████ ████████ ██ ████████ ██ ███ ██████ ██ ██████████ █████ ██████████ ████████ ███ █████████ ██ ███████
This tells us that areas that use gasoline containing MBTE have already seen an increase in headaches, fatigue, and shortness of breath in ordinary people. This strengthens the author's argument that increased use of MBTE-containing gasoline will cause increased rates of those symptoms overall.
Plausibility
Plausibility
Presenting evidence that corroborates (in Strengthen) or conflicts (in Weaken) with the author's hypothesized explanation or the predictions that follow from that explanation.
d
Regions in which ████ ████████ ██████████ ████ ██ ████ ████ █ ████ ███████ █████████ ██ ██████████ ████████ ███ █████████ ██ ██████ ████ ██ ███████ ███████ ██ █████ ████ █████████ ████████ ██ █████
Compared with MBTE-free gasoline, gasoline containing MBTE is positively correlated with headaches, fatigue, and shortness of breath. This strengthens the toxicologist's argument.
Plausibility
Plausibility
Presenting evidence that corroborates (in Strengthen) or conflicts (in Weaken) with the author's hypothesized explanation or the predictions that follow from that explanation.
e
The oil-refinery workers ████████ ████ █████████ ████████ ██ ██ ██████████████ ██ ███ ███████ ██████████ ██ █████ ███████ █████████ █████ ██ ████████ ██ █████ ██ ████ ██ ██ █████ ████████ █████████
This strengthens the toxicologist's argument, because it tells us that the survey was representative. The refinery workers in the survey weren't unusually predisposed to these symptoms for some other reason.