On October 31, a newborn baby somewhere in the world will become the 7 billi

游客2023-10-10 76

问题 On October 31, a newborn baby somewhere in the world will become the 7 billionth member of the human race. Or so says the UN—alternatively, this date could be at least a year too early. Behind the UN’s certainty may lay outdated and unreliable census data. The suspicion is that millions of births and deaths have not been counted and there is huge uncertainty about the rate at which women are giving birth. The precise "day of 7 billion" may not matter much. But the inaccuracies(不精确)make it harder to answer a more important question: is human population set to peak within the next few decades or will it carry on growing beyond that?
Wolfgang Lutz of the Vienna Institute of Demography says the UN is "under political pressure to disregard(忽视)uncertainty and name a date" for 7 billion. But he and colleague Sergei Scherbov estimate that the world probably won’t reach 7 billion until early in 2013, though it could be as late as 2020. The director of the UN population division Hania Zlotnik defends her data but agrees that "an interval of a few months or even a year would be a reasonable range of uncertainty".
One problem for demographers(人口统计学家)is undercounting. Even developed countries calculate their censuses miss up to 3 percent of people. Up-to-date figures have to adjust for both of this and the changes since the last census， which could be decades in the case of some African countries. So adjusting for extra people is routine. The big danger, Scherbov says, may be over-adjusting. The world has seen a dramatic decline in fertility in recent years, with the average woman now having only 2. 5 children, half as many as her grandmother 50 years ago. So there may be far fewer new arrivals than demographers assume.
Questions: [br] Hania Zlotnik agrees that an interval of several months or even a year would be a reasonable______.

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答案 range of uncertainty

解析由题干中的Hania Zlotnik定位到第二段最后一句．由该句可知Hania认为有几个月甚至一年的差距是在一个合理范围内的不确定性。

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