[計量] A research scientist wants to study ...

看板GRE (GRE入學考試)作者 (趴趴)時間17年前 (2008/10/24 11:19), 編輯推噓1(103)
留言4則, 1人參與, 最新討論串1/1
A research scientist wants to study a certain attribute of dogs. It is estimated that approximately 5% of all dogs have this attribute. If the scientist wants to study a sample of N dogs having the attribute, approximately how many dogs should be screened in order to obtain the desired sample size? Ans. 20N 感激^^ -- -- ※ 發信站: 批踢踢實業坊(ptt.cc) ◆ From: 118.168.65.37

10/24 11:32, , 1F
狗有5%(1/20)有attribute,研究者想研究有
10/24 11:32, 1F

10/24 11:32, , 2F
attribute的N個樣本,所以得找20N隻狗
10/24 11:32, 2F

10/24 11:33, , 3F
這樣就有20N*5%機率得到N個有效樣本
10/24 11:33, 3F

10/24 11:33, , 4F
機率5%
10/24 11:33, 4F
文章代碼(AID): #190JxUki (GRE)
文章代碼(AID): #190JxUki (GRE)