سؤال قراءة ستيب محلول — فهم التفاصيل (تدريب 7843)

1) There's a lot more to trying to evaluate whether a particular risk is big or small than you might think. Flying in airplanes is a case in point. 2) You'd think that you could determine the numbers and the odds and that would be it. The annual risk of being killed in a plane crash for the average American is about 1 in 11 million. On that basis, the risk looks pretty small. Compare that, for example, to the annual risk of being killed in a motor vehicle crash for the average American, which is about 1 in 5,000. 3) But if you think about those numbers, problems occur right away. Some people fly more and some fly less and some don't fly at all. So if you take the total number of people killed in commercial plane crashes and divide that into the total population, the result, the risk for the average American, may be a good general guide to whether the risk is big or small, but it's not specific to your personal risk. 4) Then there is another numbers problem: You can calculate the risk of flying by dividing the number: 1. Of people who die into the total number of people, which gives you the risk for the average person; 2. Of victims into the number of total flights all passengers took, which gives the risk per flight; and some don't fly at all. 3. Of victims into the total number of miles all of them flew, which gives you the risk per mile. So, if you take the total number of people killed in commercial plane crashes and divide that into the total population, the result, the risk for the average American, may be a good general guide to whether the risk is big or small, but it's not specific to your personal risk. 5) They all produce accurate numbers, but which one is most relevant to you depends on your personal flying patterns. Some fliers take lots of short flights and some take longer ones. Since the overwhelming majority of the few plane crashes that do occur take place in connection with takeoffs and landings, the risk is less a matter of how far you fly and more a matter of how often. If you are a frequent flier, then the risk per flight means more. For occasional long-distance fliers, the risk per mile means more. A frequent, long-distance flier would want to consider both.