Toxicologist: A survey of oil-refinery workers

Answer choices

1. A

   Strengthens7% picked this

   Most oil-refinery workers who do not work with MBTE do not have serious health problems involving headaches, fatigue,

   This suggests that oil-refinery workers not exposed to MBTE do not experience these symptoms, reinforcing the causal link between MBTE and the symptoms. This is the classic "No Cause, No Effect" plausibility strengthener.

   7%
2. B

   Correct79% picked this

   Headaches, fatigue, and shortness of breath are among the symptoms of several medical conditions that are potentially serious

   Why this is right

   This states that the symptoms are common to several medical conditions but doesn't address the causal link to MBTE or support the prediction about the general population, making it irrelevant to the argument.

   Skill tested: Strengthen · how this choice captures the argument's function is the move to repeat next time.

   79%
3. C

   Strengthens1% picked this

   Since the time when gasoline containing MBTE was first introduced in a few metropolitan areas, those areas reported an increase in the number of

   This makes the author's causal assumption that MBTE causes these symptoms more plausible, by providing data points where "cause is present, effect is present". It's a temporal correlation, that we didn't see the symptoms until MBTE was introduced.

   1%
4. D

   Strengthens2% picked this

   Regions in which only gasoline containing MBTE is used have a much greater incidence of headaches, fatigue, and shortness of breath than do similar

   This provides more correlative data that where MBTE is present, the symptoms are present, and where it is absent, the symptoms are absent, supporting the causal assumption that MBTE leads to these symptoms.

   2%
5. E

   Strengthens11% picked this

   The oil-refinery workers surveyed were carefully selected to be representative of the broader population in their medical histories prior to exposure to MBTE, as

   This notes that the surveyed workers were representative of the broader population, supporting the extrapolation that the general population could experience similar symptoms when MBTE use becomes widespread.

   11%