大專statistics問題

2013-04-29 4:30 am
(c) An English literature class consists of 6 male students and 4 female students.
An examination is given and the students are ranked according to their performance
Assume that no two students obtain the same score.

(i) How many different rankings are possible?

(ii) If the male students are ranked just among themselves and the female
students among themselves, how many different rankings are possible?


(iii) Four students are randomly selected from this class such that each of the
selected students is required to write an essay on one of the four different
topics. In how many ways can the essay topics be assigned if

(1) the student with the lowest examination score is NOT selected?

(2) the numbers of male and female students selected are equal?

回答 (1)

2013-04-29 6:46 am
✔ 最佳答案
(c)(i) There are 10! different rankings are possible

(ii) There are 6! * 4! different rankings are possible?

(iii)(1) There are C(9,4) * 4^4 = 32256 ways

(2) There are C(6,2) * C(4,2) * 4^4 = 23040 ways


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