The lifetimes X of a certain brand of component used in a machine can be modeled as a random variable with pdf f(x) = (1/θ) e-(x/θ). The reliability R(x) of the component is de?ned as R(x) = 1 - F(x). Suppose X1, X2,..., Xn are the lifetimes of n components randomly selected and tested. Find the MLE of R(x).