[理工] 台大電子102 工程機率
Five people gets on an elevator on the first floor of an 11-story building.
Assume that each person selects a destination floor from 10 possible floors
(i.e. from 2 to 11) uniformly and independently of others.
Also, assume that no people get on the elevator above the first floor.
Let S be the expected number of stops this elevator makes above the first
floor, and Z be the sum of all digits(including all decimal places) in S.
Then which of the following statements is true
(A) 15 <=Z<= 19
(B) 19 <=Z<= 22
(C) 22 <=Z<= 24
(D) 24 <=Z<= 25
(E) none of the above
-----------------------------------------------------------------------------
我看答案上面寫的是 (B) ,然後詳解寫
10/5 + 9/4 + 8/3 + 7/2 + 6/1 = 16.4 Z = 20
請問一下這算法是幾何分佈的嗎 ? 為什麼阿?
這題有沒有人可以詳細解說一下, 謝謝了
--
※ 發信站: 批踢踢實業坊(ptt.cc)
◆ From: 111.246.12.73
推
01/14 19:25, , 1F
01/14 19:25, 1F
→
01/14 19:25, , 2F
01/14 19:25, 2F
→
01/14 23:58, , 3F
01/14 23:58, 3F
→
01/15 00:31, , 4F
01/15 00:31, 4F
討論串 (同標題文章)
以下文章回應了本文:
完整討論串 (本文為第 1 之 2 篇):