close
標題:
Probability?
此文章來自奇摩知識+如有不便請留言告知
發問:
1.For binomial rv X,mean =26.491 S.D.=3.8205.FindP(X=x)for the mode 2.If X~B(15,0.222) Find P(4≦X≦9)
最佳解答:
1. E(X) = n p = 26.491 V(X) = n p ( 1 - p ) = 3.82052 1 - p = 3.82052 / 26.491 ≒ 0.551 p = 1 - 0.551 = 0.449 n = 26.491 / p = 26.491 / 0.449 = 59 P( X = x ) = C(59,x) * 0.449^x * 0.551^(59-x) ..... Ans 2. P( X = x ) = C(15,x) * 0.222^x * ( 1 - 0.222 )^(15-x) = C(15,x) * 0.222^x * 0.778^(15-x) P( 4 ≦ X ≦ 9 ) = Σ C(15,x) * 0.222^x * 0.778^(15-x) , from x = 4 to x = 9 ≒ 0.20957 + 0.13156 + 0.06257 + 0.02295 + 0.00655 + 0.00145 ≒ 0.435 ..... Ans
其他解答:
文章標籤
全站熱搜
留言列表
