5. Let X , X2.... X represent a random sample from a Rayleigh distribution with probability density function f(x, 0) = -e-x2/(28) x>0 a. It can be shown that E(X2) = 20. Use this fact to construct an unbiased estimator of 0 based on E X? (and use the rules of expected value to show that it is unbiased). b. Estimate 0 from the followingn = 10 observations on vibratory stress of a turbine blade under specified conditions: 16.88 10.23 4.59 6.66 13.68 14.23 19.87 9.40 6.51 10.95