※ 引述《s911125 (江小LO)》之铭言： : a factory produces 10 glass comtainers daily.itmay be assumed that there is a : constant probability p=0.1 of producing a defective container.before these : containers are stored they are inspected and defective ones are set aside. : suppose that there is a constant probalility r=0.1 that a defective container : is misclassified.let X equal the number of containers classified as defective : at the end of a production day.(suppose that all containers which are : manufactured on a particular day are also inspected on that day.) compute : P(X=2)? : a. 0.1937 : b. 0.1714 : c. 0.2541 : d. none of above : 我的算法 1. 10C2*0.1^2*0.9^8=0.1937 : 2. 10C2*0.01^2*0.99^8=0.00415 : 请问哪个P是正确的 0.1 & 0.01 由机率总和定理: 则经过检测後的不良率=0.9*0+0.1*0.9=0.09 let X equal the number of containers classified as defective at the end of a production day X~B(10, 0.09) 则P(X=2)= C(10,2)* 0.09^2 *0.91^8 =0.1714 =>故选b. 不晓得和你手上的答案是否相同@@ -- 也许我们都已经活得太自由 忘了该预习自惭形秽的本能...... --

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