Many people joke about Friday the thirteenth being an unlucky day, but a study showed that in one year approximately 17 percent of people scheduled to fly canceled or did not show up for their flights on Friday the thirteenth—a rate higher than that on any other day and date in that year. This shows that a significant percentage of the population would rather disrupt their travel plans than risk flying on a supposedly unlucky day.
Summarize Argument: Phenomenon-Hypothesis
The author hypothesizes that a significant proportion of the population are willing to disrupt their plans to avoid flying on an “unlucky” Friday the thirteenth. This hypothesis is based on the observation that during a particular year, more people cancelled or didn’t show up to their flights on Friday the thirteenth than on any other day that year.
Notable Assumptions
The author assumes that the reason people didn’t show up for their flights on Friday the thirteenth was the unlucky date, and not some other reason. There aren’t that many Fridays the thirteenth in a single year, so maybe some other significant factor just happened to arise on one or more Fridays the thirteenth that year.
A
People who fly tend to be professionals who as a group are less superstitious than the general public.
Even if people who fly are less superstitious, that doesn’t mean they’re not superstitious—maybe an even higher percentage of the general public would have skipped their flights. This doesn’t provide an alternative explanation, or make the author’s explanation any less likely.
B
Surveys show that less than 5 percent of the population report that they believe that Friday the thirteenth is an unlucky day.
This just doesn’t give us enough context to know how it relates to the 17 percent of people who missed their flights on Friday the thirteenth. Maybe only a very tiny percentage of people fly, and they’re unusually likely to be superstitious—we don’t know.
C
Weather conditions at several major airports were severe on the Fridays that fell on the thirteenth in the year of the study.
This weakens by providing an alternative explanation for why more people missed their flights on Friday the thirteenth. If there happened to be severe weather those days, it makes sense that people would miss their flights even without superstition being involved.
D
In the year of the study, automobile traffic was no lighter on Friday the thirteenth than on other Fridays.
This does not weaken, because the domain of the argument is specific to flights. It would be perfectly reasonable for people to fear flying on an unlucky day but not fear driving, because driving is a much more routine activity.
E
The absentee rate among airline workers was not significantly higher than normal on the Fridays that fell on the thirteenth in the year of the study.
This does not weaken, because there are other factors that explain why airline workers might show up to work on an “unlucky” day. So this doesn’t really contradict the observed data about passengers, and still doesn’t explain the phenomenon.
First, the site is suitable. There’s enough space for the building and no smog or light pollution from nearby cities.
Second, it would protect ecology, not harm it as some critics fear. The mountain currently has many recreational users who threaten its ecology, but recreational use would be precluded by the observatory.
The astronomer also assumes that the process of building the observatory, and the building’s ongoing presence on the mountain, wouldn’t harm the mountain’s ecology more than the current recreational use does.
A
More than a dozen insect and plant species endemic to Mount Shalko are found nowhere else on earth.
B
A coalition of 14 different groups, as diverse as taxpayer organizations and hunting associations, opposes the building of the new observatory.
C
Having a complex that covers most of the summit, as well as having the necessary security fences and access road on the mountain, could involve just as much ecological disruption as does the current level of recreational use.
D
The building of the observatory would not cause the small towns near Mount Shalko eventually to develop into a large city, complete with smog, bright lights, and an influx of recreation seekers.
E
A survey conducted by a team of park rangers concluded that two other mountains in the same general area have more potential for recreational use than Mount Shalko.