Cars are safer than planes. Fifty per cent of plane accidents result in death, while only one percent of car accidents result in death.
Which of the following, if true, would most seriously weaken the argument above?
Planes are inspected more often than cars.
The number of car accidents is several hundred thousand times higher than the number of plane accidents.
(Correct Answer)Pilots never fly under the influence of alcohol, while car drivers often do.
Plane accidents are usually the fault of air traffic controllers, not of pilots.
The number of car accidents is several hundred thousand times higher than the number of plane accidents.
Step 1: Identify the Conclusion
The conclusion of the argument is: "Cars are safer than planes."
Step 2: Analyze the Evidence
The argument bases this conclusion on the fatality rate per accident:
Plane accidents: 50% result in death.
Car accidents: 1% result in death.
Step 3: Evaluate the Logical Flaw
The argument assumes that because a single car accident is less likely to be fatal than a single plane accident, cars are "safer" overall. However, "safety" is usually measured by the total number of deaths or the probability of being in an accident in the first place.
Step 4: Test the Options
(a) Inspections: This explains why planes might be safe, but it doesn't directly challenge the comparison of fatality percentages.
(b) Frequency of accidents: If car accidents happen hundreds of thousands of times more often than plane accidents, the total number of deaths in cars could be much higher, even with a lower percentage per accident. For example:
If there is 1 plane accident, deaths = 0.5.
If there are 1,000,000 car accidents, deaths = 1% of 1,000,000=10,000.
This shows that the risk of dying in a car is actually much higher because accidents are so frequent.
(c) Alcohol: This explains a cause for accidents but doesn't weaken the statistical comparison provided.
(d) Fault/Responsibility: Knowing who is at fault (pilots vs. controllers) does not change the safety statistics.
Conclusion
Option (b) provides the context of "total volume," which proves that the percentage of deaths per accident is a misleading way to measure overall safety.
Correct Option: (b)
Step 1: Identify the Conclusion
The conclusion of the argument is: "Cars are safer than planes."
Step 2: Analyze the Evidence
The argument bases this conclusion on the fatality rate per accident:
Plane accidents: 50% result in death.
Car accidents: 1% result in death.
Step 3: Evaluate the Logical Flaw
The argument assumes that because a single car accident is less likely to be fatal than a single plane accident, cars are "safer" overall. However, "safety" is usually measured by the total number of deaths or the probability of being in an accident in the first place.
Step 4: Test the Options
(a) Inspections: This explains why planes might be safe, but it doesn't directly challenge the comparison of fatality percentages.
(b) Frequency of accidents: If car accidents happen hundreds of thousands of times more often than plane accidents, the total number of deaths in cars could be much higher, even with a lower percentage per accident. For example:
If there is 1 plane accident, deaths = 0.5.
If there are 1,000,000 car accidents, deaths = 1% of 1,000,000=10,000.
This shows that the risk of dying in a car is actually much higher because accidents are so frequent.
(c) Alcohol: This explains a cause for accidents but doesn't weaken the statistical comparison provided.
(d) Fault/Responsibility: Knowing who is at fault (pilots vs. controllers) does not change the safety statistics.
Conclusion
Option (b) provides the context of "total volume," which proves that the percentage of deaths per accident is a misleading way to measure overall safety.
Correct Option: (b)
