Answer Happy

Question 4 a) State the probability mass function p.m.f. of the Poisson variable with mean X. [1 b) A shop sells a particular make of smart phone. It is assumed that the daily sales of this type of phone is a Poisson variable with mean 3. Find the probability, giving the answers in terms of e, that on a particular day the shop sells: i) exactly 3 smart phones. [2 ii) at least 4 smart phones. [3 c) It is further given that in a particular day at least 4 smart phones were sold. Show that the probability that exactly 7 smart phones were actually sold that day is given by 243 k(e³ - 13)' where k is an integer to be found. [4