In: Math
. Assume that the lifetimes (measured from the beginning of use) of lightbulbs are i.i.d. random variables with distribution P(T ≥ k) = (k + 1)−β , k = 0, 1, 2, . . . , for some β > 0. (Note that time is measured in discrete units.) In a lightbulb socket in a factory, a bulb is used until it fails, and then it is replaced at the next time unit. Let (Xn)n≥0 be the irreducible Markov chain which records the age of the bulb currently in use in the socket (Xn = 0 at times when a bulb is replaced, corresponding to a new bulb). (a) Derive the transition probabilities of the chain. (b) For each value of β, determine if the chain is positive recurrent, null recurrent, or transient.