[問題] variance of a random sample
我做了一題交大財金的題目
有個地方我算的跟解答有出入
Let S^2 denote the variance of a random sample of size n>1 from
N(m,@), 0<@<infinity. (Note: S^2 is the MLE of @)
Is (n/n-1)S^2 an unbiased estimator of @?
我用 (n-1)S^2/@ ~Chi(n-1)
算出來不是不偏
但解答確是用 nS^2/@ ~Chi(n-1) 得出他是不偏
而且後面的小題也是用 nS^2/@比較好算
但樣本變異不是除n-1嗎?
這樣不就應該是乘 n-1 而非 n?
不好意思因為用手機排版可能很亂,我回家會再調。
謝謝大家了!
--
※ 發信站: 批踢踢實業坊(ptt.cc)
◆ From: 1.167.87.115
→
11/20 19:30, , 1F
11/20 19:30, 1F
→
11/20 19:30, , 2F
11/20 19:30, 2F
→
11/20 19:30, , 3F
11/20 19:30, 3F
推
11/20 19:35, , 4F
11/20 19:35, 4F
→
11/20 19:35, , 5F
11/20 19:35, 5F
→
11/21 18:02, , 6F
11/21 18:02, 6F
→
11/21 18:03, , 7F
11/21 18:03, 7F
推
11/21 19:49, , 8F
11/21 19:49, 8F
→
11/21 19:50, , 9F
11/21 19:50, 9F
→
11/22 00:55, , 10F
11/22 00:55, 10F
推
11/22 07:04, , 11F
11/22 07:04, 11F
→
11/22 13:50, , 12F
11/22 13:50, 12F