更新1:
i don't understand why mean is k?
dispersion
回答 (2)
2008-12-05 5:49 am
✔ 最佳答案
Mean = 5k/5 = k.so [k - 7 - k}^2 = 49
[k - 3 - k]^2 = 9
[k - k]^2 = 0
[k + 4 - k]^2 = 16
[k + 6 - k]^2 = 36
sum = 110
sum/5 = 110/5 = 22
S.D. = sqrt(22).
2008-12-05 21:36:06 補充：
Mean = average = [(k-7) + (k-3) + k + (k+4) + (k+6)]/5 = 5k/5 = k.
2008-12-05 6:38 am
E(X) = k
E(X ^ 2) = (k ^ 2) + 22
Var (X) = E(X ^ 2) - {[E(X)] ^ 2} = 22
standard deviation = sqrt (22)
E(X ^ 2) = (k ^ 2) + 22
Var (X) = E(X ^ 2) - {[E(X)] ^ 2} = 22
standard deviation = sqrt (22)
收錄日期: 2021-04-23 18:16:02
原文連結 [永久失效]:
https://hk.answers.yahoo.com/question/index?qid=20081204000051KK01518