b:head_first_statistics:permutation_and_combination
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b:head_first_statistics:permutation_and_combination [2019/10/28 11:44] – [e.g.] hkimscil | b:head_first_statistics:permutation_and_combination [2023/10/11 08:16] (current) – [e.g.] hkimscil | ||
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+ | ====== Permutation and Combination ====== | ||
+ | 순열과 조합 | ||
====== Permutation ====== | ====== Permutation ====== | ||
+ | |||
세마리 말이 들어오는 순서 | 세마리 말이 들어오는 순서 | ||
{{: | {{: | ||
Line 69: | Line 72: | ||
b, a2, a1 | b, a2, a1 | ||
- | n! / p! x q! | + | $$ \frac {n!} {p! * q!} $$ |
+ | < | ||
{{: | {{: | ||
+ | |||
6 horses | 6 horses | ||
2 groups 3 horses per each group | 2 groups 3 horses per each group | ||
+ | |||
+ | {{: | ||
< | < | ||
Line 88: | Line 94: | ||
{{: | {{: | ||
{{: | {{: | ||
+ | |||
+ | <WRAP box> | ||
+ | X = {a a b c c c} 라면? | ||
+ | n(X) = 6 이므로 총 6! | ||
+ | a가 둘, c가 셋으로 묶이므로 | ||
+ | 6! / (2! * 3!) | ||
+ | = 6*5*2 = 60 | ||
+ | |||
+ | |||
+ | </ | ||
<WRAP box> | <WRAP box> | ||
Line 150: | Line 166: | ||
C A | C A | ||
+ | \begin{eqnarray*} | ||
+ | _{3}P_{2} & = & \frac{3!}{(3-2)!} \\ | ||
+ | & = & \frac {3!}{(3-2)!} = 6 | ||
+ | \end{eqnarray*} | ||
+ | |||
+ | Among the two, the order doesn' | ||
2 representatives | 2 representatives | ||
A B | B A | A B | B A | ||
Line 156: | Line 178: | ||
\begin{eqnarray*} | \begin{eqnarray*} | ||
- | _{3}C_{2} * 2! & = & _{3}P_{2} \\ | + | \text{Answer we want} & = & \frac {_{3}P_{2}}{2!} \\ |
- | _{3}C_{2} & = & \frac {_{3}P_{2}}{2!} \\ | + | \text{We call this} & = & _{3}C_{2} \\ |
_{3}C_{2} & = & \frac {\frac{3!}{(3-2)!}} {\frac {2!} {1}} \\ | _{3}C_{2} & = & \frac {\frac{3!}{(3-2)!}} {\frac {2!} {1}} \\ | ||
- | _{3}C_{2} & = & \frac {3!}{2! * (3-2)!} = 6 | + | _{3}C_{2} & = & \frac {3!}{2! * (3-2)!} = 3 |
\end{eqnarray*} | \end{eqnarray*} | ||
Line 195: | Line 217: | ||
2. The coach classes 3 of the players as expert shooters. What’s the probability that all 3 of these players will be on the court at the same time, if they’re chosen at random? | 2. The coach classes 3 of the players as expert shooters. What’s the probability that all 3 of these players will be on the court at the same time, if they’re chosen at random? | ||
</ | </ | ||
+ | |||
< | < | ||
## n! / r!(n-r)! | ## n! / r!(n-r)! | ||
Line 233: | Line 256: | ||
A flush is where all 5 cards belong to the same suit. What’s the probability of getting this? | A flush is where all 5 cards belong to the same suit. What’s the probability of getting this? | ||
</ | </ | ||
+ | {{https:// | ||
+ | see [[wp> | ||
+ | {{https:// | ||
< | < | ||
## 52장의 카드 중에서 5장 고를 조합은 | ## 52장의 카드 중에서 5장 고를 조합은 |
b/head_first_statistics/permutation_and_combination.1572230695.txt.gz · Last modified: 2019/10/28 11:44 by hkimscil