In 90 percent of the commercial airline accidents last year, one or
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09 Mar 2024, 19:47
In 90 percent of the commercial airline accidents last year, one or another of a group consisting of only 18 percent of the world’s commercial airlines was involved. Since the other 82 percent of airlines were generally flying the same types of airplanes as the accident-prone airlines, significant differences in safety procedures must have been responsible for these differences in safety records.
The conclusion of the argument is the following:
significant differences in safety procedures must have been responsible for these differences in safety records
The support for the conclusion is the following:
the other 82 percent of airlines were generally flying the same types of airplanes as the accident-prone airlines
So, the reasoning of the argument is basically that, since there was no difference between the planes of the airlines involved in accidents and the planes of those that were not, differences in safety procedures must have been the cause of the differences in safety records.
Simply put, the reasonining is that, since one particular thing didn't cause the difference in safety records, one other particular thing caused it.
One thing we might notice about the way the conclusion is supported is that, in concluding that differences in safety procedures must have been responsible for the differences in safety records, the argument ignores the fact that there are many possible causes of the difference in safety records other than differences in safety procedures.
Which of the following, if true about the world’s commercial airlines last year, most seriously weakens the argument above?
This is a Weaken question. So, the correct answer will provide information that indicates that the conclusion doesn't necessarily follow from the evidence.
A. Fifteen percent of the airlines were responsible for 97 percent of all air miles flown, and those airlines were involved in 87 percent of the accidents.
This choice weakens the argument by indicating that it's quite likely that something other than differences in safety procedures is responsible for the differences in safety records.
After all, if what this choice says is true, then the vast majority of the accidents involved 15 percent of airlines only because those airlines did almost all, 97 percent, of the flying. After all, we'd expect that airlines that did almost all the flying would be involved in the vast majority of the accidents regardless of whether they have safety procedures different from those of other airlines.
Furthermore, notice that this choice indicates that, even though the airlines mentioned by this choice did 97 percent of the flying, they were involved in only 87 percent of the accidents. So, actually, their safety records were slightly better than average, a fact that indicates that their safety procedures were not the cause of the accidents.
So, this choice clearly casts doubt on the conclusion.
Keep.
B. The accident-prone airlines were cited by their governments for a significantly higher number of safety violations than were the other airlines.
If anything, this choice strengthens, rather than weakens, the argument.
After all, it indicates that the airlines involved in accidents likely did have safety procedures different from those of the other airlines. After all, it seems likely that what would cause differences in numbers of safety violations is some kind of differences in procedures related to safety.
Eliminate.
C. After an airline is involved in a serious accident, many of its regular customers switch to another airline, and some flights are canceled.
This information about what happens after an airline is involved in an accident does not indicate anything about what caused the accidents that occurred last year.
So, this choice has no effect on the strength of the argument.
Eliminate.
D. Twenty percent of the airlines employ personnel currently serving in their country’s armed forces.
This choice tempts us to choose it by using a value, "twenty percent," that's close to percentage of airlines involved in accidents last year, "18 percent."
At the same time, this choice has no effect on the strength of the argument because the implications for safety of the fact that some airlines employ personnel currently serving in armed forces are not clear. Also, it's not even clear that the twenty percent of airlines mentioned in this choice are mostly the same airlines as the 18 percent of airlines mentioned in the passage. So, what if any relationship this choice has with the situation presented by the passage is not clear.
Thus, this choice has no clear effect on the argument.
Eliminate.
E. Twenty-four percent of the airplanes in regular service are over fifteen years old.
This choice tempts us to choose it by using a value, "twenty-four percent," that's relatively close to percentage of airlines involved in accidents last year, "18 percent."
At the same time, this choice has no effect on the strength of the argument because the implications for safety of the fact that some planes are over fifteen years old are not clear. Are planes over 15 years old more likely to be involved in accidents than other planes? Maybe, but maybe not.
Also, it's not even clear that any of the twenty-four percent of planes mentioned by this choice were involved in accidents. For all we know, none of the planes over 15 years old were involved in accidents last year, in which case the fact that 24 percent of the planes are over 15 years old would likely have no relationship with the fact that there were accidents.
So, this choice has no clear relevance to the argument and thus doesn't weaken it.
Eliminate.
Correct answer: A