Self-study
Support A year ago the government reduced the highway speed limit, and Support in the year since, there have been significantly fewer highway fatalities than there were in the previous year. ██████████ █████ █████ █████████ ███ ██████ ███████ ███████████
Summarize Argument: Phenomenon-Hypothesis
The author concludes that a speed limit reduction can reduce traffic fatalities. This is based on the fact that a year ago, the government reduced the highway speed limit, and in the year since that reduction, there have been fewer highway deaths than there were in the previous year.
Identify and Describe Flaw
The author assumes that the reduction in highway speed limit caused the decrease in highway fatalities. This overlooks the possibility that there are other explanations for the decrease in highway fatalities in the year following the speed limit reduction.
17.
The argument is most vulnerable ██ ███ █████████ ████ ██ █████ ███ ███████ ████
a
highway traffic has ███ █████████ ████ ███ ████ ████
The negation of (A) doesn’t undermine the argument. If traffic has increased over the past year, that might strengthen the argument, because we’d expect to see more fatalities. Since the negation doesn’t hurt the argument, the author doesn’t have to assume (A).
b
the majority of ███████ ██████ ███ ███ █████ █████
The author doesn’t have to assume that most drivers obeyed the speed limit, because a speed limit reduction can still affect driving behavior even if most people don’t follow the speed limit. For example, the new limit can cause people to drive slower.
c
there is a ████████ ███████ ███████ █████ ███ ███ ██████ ██ ██████████ █████████
The author’s conclusion concerns the number of highway deaths. This doesn’t commit the author to any belief about the number of accidents, which is different from the number of deaths.
d
the new speed █████ ███ ████ ████████ ████████ ████ ███ ███
If anything, the author assumes that the new speed limit was not more strictly enforced. More strict enforcement could have been an alternate explanation for the decline in fatalities. So the author assumes this didn’t happen, not that it did happen.
e
the number of ███████ ██████████ ███ ████ ██████ ███ ███ █████ █████ ███ ██████████ ███ ███ ██████████ ████
This must be assumed because if the number of fatalities the year before the new limit was abnormally high, then that suggests the decrease in fatalities after the speed limit might just be a coincidence. It might be a return to the normal fatality rate.