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】![](/moin_static193/solenoid/img/up.png) : 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
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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】![](/moin_static193/solenoid/img/up.png) : 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
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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】![](/moin_static193/solenoid/img/up.png) : 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。
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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】![](/moin_static193/solenoid/img/up.png) : 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。
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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】![](/moin_static193/solenoid/img/up.png) : 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
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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】![](/moin_static193/solenoid/img/up.png) : {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。
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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】![](/moin_static193/solenoid/img/up.png) : 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
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d****0 发帖数: 335 | |