OG 174,没人讨论过吧

leojin

174. 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.

Given that the incidence rate for sinusitis is the same for people of all ages, and that the average age of the
population will increase, if follows that the average age of people suffering from sinusitis will increase. Therefore, C is the best answer.

什么道理人口的平均年龄会增加？牛人请帮我解释一下

crossrose

不是牛人， 试着解释一下。 人口平均年龄会增加在这道题里是一个必要条件。因为那个窦炎的的发病率与人的年龄无关，所以人口的平均年龄增加了，人发病的几率就越大。就象一个人本来活50岁，没有得窦炎，实际上他可能在60岁的时候会发病，所以他如果活到60岁，就会发这个病了。

好拗口的解释，不知道你看不看的懂

leojin

我就没明白，为什么人口的平均年龄会增加呢？你所谓的必要条件从何而来？

leojin

wok，看错题目了……

lindazhou

i can't understand, please explain it for me . thanks

携隐

以前有两个讨论贴，其中还有一个是精华。请搜索。

smiletotem

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.

so,(C) The average age of people suffering from sinusitis will increase between 1987 and 2000

is right

sinusitis各个年龄层都会得，而社会平均年龄上升。所以sinusitis患者平均年龄上升。一句话，算术平均值向上漂移了。

flylion

几年过来　人的年龄都长了以前没有的人现在也会得　所以．．．．．．．

deefox2002

以下是引用flylion在2005-6-1 2:33:00的发言：
几年过来　人的年龄都长了以前没有的人现在也会得　所以．．．．．．．

为什么？有没哪位牛牛再解释一下！谢谢！

[此贴子已经被作者于2005-10-24 17:29:58编辑过]

deefox2002

以下是引用携隐在2005-5-31 13:20:00的发言：

以前有两个讨论贴，其中还有一个是精华。请搜索。

对不起，现在搜索找到的只有这个贴子了。没看到你说的其他的贴子。