Support In an experiment, ten people were asked to taste samples of coffee and rank them. Five of the people were given chocolate with the coffee, and this group subsequently reported that all the coffee samples tasted pretty much the same as one another. Five others tasted coffee only, and they were able to detect differences. Clearly, then, Conclusion chocolate interferes with one's ability to taste coffee.
The author hypothesizes that chocolate interferes with one’s ability to taste coffee. The evidence? An experiment where two groups tasted coffee samples, one with chocolate and one without. The chocolate group couldn't distinguish the coffee samples, but the non-chocolate group could all taste the differences.
The author draws a general conclusion from an experimental study, which requires two assumptions. Denying either assumption would weaken the argument.
The first assumption is that there was no relevant difference between the two groups other than the chocolate. Any other relevant difference between the two groups would call into question the author’s hypothesis by suggesting a different cause for the outcome.
The second assumption is that this experiment is representative of how chocolate affects the ability to taste coffee for everyone. In other words, the author assumes that a single study with ten people is sufficient to draw conclusions about all people.
Which one of the following, if true, most undermines the conclusion drawn above?
The ten people were randomly assigned to either the group that tasted only coffee or the group that was also given chocolate, although some people had asked to be in the group that received chocolate.
This almost weakens, but not quite: because those people who wanted to be in the chocolate group were nevertheless randomly assigned, the experiment remains intact.
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).
Similar results were achieved when the experiment was repeated with a different, larger group of people.
This strengthens the author’s argument by affirming the author's assumption about representativeness. Another study with the same result makes it that much more likely that the findings are true for all people.
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).
Chocolate is normally consumed as a solid, whereas coffee is normally consumed as a liquid.
We have no reason to think that the difference between solid and liquid foods is relevant to how people perceive taste, or whether tastes can interfere with each other. As far as we know, this isn't relevant.
The five people who were originally given chocolate were asked a week later to taste coffee samples without chocolate, and they still detected no differences between the coffee samples.
In other words, the chocolate group might simply have no ability to taste the differences between coffee samples. This denies the author's assumption about relevant differences, and weakens by presenting a new factor that better explains the difference between the groups.
Presenting evidence that corroborates (in Strengthen) or conflicts (in Weaken) with the author's hypothesized explanation or the predictions that follow from that explanation.
Some subjects who tasted just coffee reported only subtle differences between the coffee samples, while others thought the differences were considerable.
Regardless of the strength of the differences, these people all noted differences, whereas people in the chocolate group didn’t note any differences. This doesn't change the result or add new relevant information, so it's not useful.
Answer is attractive because it seems to (but doesn't actually) contradict the premises or conclusion.
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