大全-9-19

DARRENMA

In 1987 sinusitis was the most common chronic medical condition in the United States, followed by arthritis and high blood pressure, in that order.
The incidence rates for both arthritis and high blood pressure increase with age, but the incidence rate for sinusitis is the same for people of all ages.
The average age of the United States population will increase between 1987 and 2000.

Which of the following conclusions can be most properly drawn about chronic medical conditions in the United States from the information given above?
(A) Sinusitis will be more common than either arthritis or high blood pressure in 2000.
(B) Arthritis will be the most common chronic medical condition in 2000.
(C) The average age of people suffering from sinusitis will increase between 1987 and 2000.
(D) Fewer people will suffer from sinusitis in 2000 than suffered from it in 1987.
(E) A majority of the population will suffer from at least one of the medical conditions mentioned above by the year 2000.

答案：C

题干中the incidence rate for sinusitis is the same for people of all ages.不是与C矛盾吗？看了以前的讨论贴还是不明白为何C中的age会increase?

比如说子宫肌留(举例不够雅观,都是广告惹的祸)是45岁妇女的常见病,十年后不会是55岁妇女的常见病吧?

kanstorys

我是这么理解的,不知道对不对,第一,人的平均年龄一定增加(原文说的)我们来假设一个数学模型,假设世界上在5年里不会有人出生,也不会有人死亡,(总人数不变),那么5年以后人的平均年龄就会增加,(因为平均年龄=每个人的年龄和加在一起/总人数,5年人的年龄都增加了5,所以和就增加,所以平均年龄也就增加了)满足原文,原文说the incidence rate for sinusitis is the same for people of all ages我可以理解为得病比率没变,也就是在这5年里没人得病(5年内总人数没变,得病比率没变,所以得病人也没变)那么我们就能推出得病人的平均年龄就会增加(因为,得病人数没变,而得病人每人年龄都加5,所以得病人总年龄增加,所以平均年龄就增加)

我也想了好久,要是考试碰到,只能蒙了,蒙的原则就是推论题的结论一定和原文有关,原文一直在说年龄,所以答案也一定和年龄有关.

hebbechou

将的是美国三种疾病的发病率:

(1)1987年:窦炎>关节炎>高血压,后两者发病率随年龄增加而增长;窦炎对所有年龄都相同的.

(2)1987-2000:美国人口平均年龄增加.

结论:

思考过程:

1.我们先假设1987年美国人口平局年龄50岁.根据条件2,2000年上升为60岁.

2.既然窦炎对所有年龄的人的发病率都是相同的.

那么,很显然因为美国整体平均年龄上升了,那么窦炎所发病的人群的年龄也就上升了.

不知道这么写你能否明白~在下也是才疏学浅.