※ 引述《kbamj (ya^^)》之铭言： : 麻烦各位了~有一小题不太了解~ : Calls arriving at a switchboard follow a Poisson process with parameter : λ=5.2 per minute. : 1.What is the expected waiting time between the arrivals of two calls? : 这题我想是把λ=5.2/min转成θ=23.6sec/2calls,算θ? interarrival time Ti~iid exp(1/5.2) (单位:mimute) E[Ti]=1/5.2 (mimute) : 2.What is the probability that the waiting time between the arrivals of : two calls is less than 10 seconds? : 这题就把上题θ,用指数分配,然後积分范围0~10? 计算 P(Ti<1/6) : 3.What is the distribution of the time taken for 10 calls to arrive at : the switchboard? : 他说10calls时间分配分部?不太了解~ d 题目所求 T = T1+...+T10~Gamma(10,1/5.2) : 4.What is the expectation of the time taken for 10 calls to arrive at : the switchboard? : 10calls期望值?不太了解~ E[T]=10*1/5.2 : 5.What is the probability that less than 5 calls arrive at the switchboard : during a 1-minute period? : 这题单纯算P(X<5) X=到达calls数 用Poisson? 计算 P(T1+...+T5>1), Ti+...+T5~Gamma(5,1/5.2) 或直接X~Poi(5.2), 计算P(X<5) --

※ 发信站: 批踢踢实业坊(ptt.cc) ◆ From: 140.115.45.112 ※ 编辑: Jordan23 来自: 140.115.45.112 (04/14 18:31)