jj8

Zeros

个人看法："三次朝上，两次朝下"=》且规定了顺序，就是C5,3中的一种。(1/2)^5

tyou

do it have to do with the sequence ?   for example    1st, 3rd, and last time    up
the other two    down              in this case, can we also get the answer  ：(1/2)^5  ?

Zeros

如果问：“三次朝上，两次朝下的概率是多少？”，则为：C5,3 (1/2)^5

如果限定了哪次朝上，哪次朝下，如：“前三次朝上，后两次朝下的概率？”，则为：(1/2)^5

tyou

Hi,  some people are discussing JJ8

8) 支硬币五次，朝上的概率为1/2。问前三次朝上，后两次朝下的概率？
参考答案:  (1/2)^5
思路: (1/2)^5



What is the essential difference in the questions if the answer is C5,3 (1/2)^5  or
(1/2)^5 ?

I mean how it is asked, the answer should be C5,3 (1/2)^5
and how is it asked, the answer should be (1/2)^5 ?