g*******n
发帖数: 91 | 1 If the chance of surviving for 1 year after being diagnosed with prostate
cancer is 80%, and the chance of surviving for 2 years is 60%, what is the
chance of surviving for 2 years after the diagnosis, given that the patient
is alive at the end of the first year?
A) 20%
B) 48%
C) 60%
D) 75%
E) 80%
有人选C ，也有人选D。 请问大侠们哪个正确啊？ 谢谢 |
y*****t
发帖数: 1367 | 2 选D
P(survive 2nd year|survive 1 st year)
=P(survive 1st year and survive 2nd year)/P(survive 1st year)
=P(survive 2 years)/P(survive 1 year)
=60%/80%
=75%
patient
【在 g*******n 的大作中提到】
: If the chance of surviving for 1 year after being diagnosed with prostate
: cancer is 80%, and the chance of surviving for 2 years is 60%, what is the
: chance of surviving for 2 years after the diagnosis, given that the patient
: is alive at the end of the first year?
: A) 20%
: B) 48%
: C) 60%
: D) 75%
: E) 80%
: 有人选C ，也有人选D。 请问大侠们哪个正确啊？ 谢谢
|
g*******n
发帖数: 91 | 3 真是高人，谢谢。
再请教一下：P(survive 1st year and survive 2nd year) 为什么等于P(survive 2 years) 啊？ 我总觉得应该等于 0.60*0.80 啊。
【在 y*****t 的大作中提到】
: 选D
: P(survive 2nd year|survive 1 st year)
: =P(survive 1st year and survive 2nd year)/P(survive 1st year)
: =P(survive 2 years)/P(survive 1 year)
: =60%/80%
: =75%
:
: patient
|
l*********s
发帖数: 5409 | 4 they are not independent; if one dies in the first year, he/she is not going
to surrvive the second year.
years) 啊？ 我总觉得应该等于 0.60*0.80 啊。
【在 g*******n 的大作中提到】
: 真是高人，谢谢。
: 再请教一下：P(survive 1st year and survive 2nd year) 为什么等于P(survive 2 years) 啊？ 我总觉得应该等于 0.60*0.80 啊。
|
g*******n
发帖数: 91 | 5 奥， 想不通为什么
P(survive 1st year and survive 2nd year) 就直接等于P(survive 2 years) ? 能解
释下吗？ 谢谢
going
【在 l*********s 的大作中提到】
: they are not independent; if one dies in the first year, he/she is not going
: to surrvive the second year.
:
: years) 啊？ 我总觉得应该等于 0.60*0.80 啊。
|
y*****t
发帖数: 1367 | 6 {Survive 1st year and survive 2nd year}和{Survive 2 years}是同一个集合的两个
不同定义方法而已。
years) 啊？ 我总觉得应该等于 0.60*0.80 啊。
【在 g*******n 的大作中提到】
: 奥， 想不通为什么
: P(survive 1st year and survive 2nd year) 就直接等于P(survive 2 years) ? 能解
: 释下吗？ 谢谢
:
: going
|
t******g
发帖数: 2253 | |
g*******n
发帖数: 91 | 8 谢谢，明白了这次
【在 y*****t 的大作中提到】
: {Survive 1st year and survive 2nd year}和{Survive 2 years}是同一个集合的两个
: 不同定义方法而已。
:
: years) 啊？ 我总觉得应该等于 0.60*0.80 啊。
|
b*******r
发帖数: 152 | 9 to survive for 2 yrs, one has to first survive for 1 yr. so to say that one
survives for 2 yr implies that the one has survived for 1 yr. |
a****r
发帖数: 1486 | 10 A = survive 1 yr
B = survice 2 yr
P(B | A) = ....
note : A intersection B = B
so .....
patient
【在 g*******n 的大作中提到】
: If the chance of surviving for 1 year after being diagnosed with prostate
: cancer is 80%, and the chance of surviving for 2 years is 60%, what is the
: chance of surviving for 2 years after the diagnosis, given that the patient
: is alive at the end of the first year?
: A) 20%
: B) 48%
: C) 60%
: D) 75%
: E) 80%
: 有人选C ，也有人选D。 请问大侠们哪个正确啊？ 谢谢
|
d****0
发帖数: 335 | |
