[中學] 排列組合
十個數字由大而小為30,30,40,50,60,60,60,70,80,80,
現用簡單隨機抽樣取出三個,已知所取的三個數字有一個為
70,則在此條件下,中位數為60的機率為?
我的想法是:
口 60 70
口可以放剩下沒選到的30, 30, 40, 50 ,60 ,60(因為三個60視為相同物,所以選任
何一個都一樣,所以選完一個還剩兩個)
所以答案是6/C9取2 = 1/6
請問這樣寫為什麼是錯的?
--
※ 發信站: 批踢踢實業坊(ptt.cc)
◆ From: 114.39.17.248
→
03/04 23:09, , 1F
03/04 23:09, 1F
→
03/04 23:09, , 2F
03/04 23:09, 2F
→
03/04 23:10, , 3F
03/04 23:10, 3F
→
03/04 23:11, , 4F
03/04 23:11, 4F
→
03/04 23:14, , 5F
03/04 23:14, 5F
→
03/04 23:59, , 6F
03/04 23:59, 6F
→
03/05 00:00, , 7F
03/05 00:00, 7F
→
03/05 00:19, , 8F
03/05 00:19, 8F
→
03/05 00:23, , 9F
03/05 00:23, 9F
→
03/05 00:24, , 10F
03/05 00:24, 10F
→
03/05 00:25, , 11F
03/05 00:25, 11F
→
03/05 00:26, , 12F
03/05 00:26, 12F
→
03/05 00:29, , 13F
03/05 00:29, 13F
→
03/05 00:29, , 14F
03/05 00:29, 14F
→
03/05 00:36, , 15F
03/05 00:36, 15F
→
03/05 00:36, , 16F
03/05 00:36, 16F
→
03/05 00:37, , 17F
03/05 00:37, 17F
→
03/05 00:37, , 18F
03/05 00:37, 18F
→
03/05 00:39, , 19F
03/05 00:39, 19F
→
03/05 00:39, , 20F
03/05 00:39, 20F
→
03/05 00:41, , 21F
03/05 00:41, 21F
→
03/05 00:42, , 22F
03/05 00:42, 22F
→
03/05 00:43, , 23F
03/05 00:43, 23F
→
03/05 00:45, , 24F
03/05 00:45, 24F
→
03/05 00:46, , 25F
03/05 00:46, 25F
→
03/05 00:47, , 26F
03/05 00:47, 26F
→
03/05 00:48, , 27F
03/05 00:48, 27F
→
03/05 00:49, , 28F
03/05 00:49, 28F
→
03/05 00:49, , 29F
03/05 00:49, 29F
→
03/05 00:50, , 30F
03/05 00:50, 30F
→
03/05 00:51, , 31F
03/05 00:51, 31F
→
03/05 00:52, , 32F
03/05 00:52, 32F
→
03/05 00:53, , 33F
03/05 00:53, 33F
→
03/05 00:54, , 34F
03/05 00:54, 34F
→
03/05 00:55, , 35F
03/05 00:55, 35F
→
03/05 01:00, , 36F
03/05 01:00, 36F
→
03/05 01:00, , 37F
03/05 01:00, 37F
→
03/05 01:00, , 38F
03/05 01:00, 38F
→
03/05 01:00, , 39F
03/05 01:00, 39F
→
03/05 01:01, , 40F
03/05 01:01, 40F
→
01/02 15:41,
5年前
, 41F
01/02 15:41, 41F
→
07/07 11:55,
5年前
, 42F
07/07 11:55, 42F
討論串 (同標題文章)