Let x1, x2, , xn be a random sample of size n from the exponential distribution whose pdf is f(x; θ) = (1/θ)e−x/θ , 0 < x < [infinity], 0 < θ< [infinity].(a) show that x is an unbiased estimator of θ.(b) show that the variance of x is θ 2/n.(c) what is a good estimate of θ if a random sample of size 5 yielded the sample values 3.5, 8.1, 0.9, 4.4, and 0.5?