21. Suppose that a random sample XX

21. Suppose that a random sample XXn is to be taken from a normal distribution with unknown mean 0 and variance 100, and the prior distribution of 0 a normal distribution with specified mean U and variance 25. Suppose that 0 is to be estimated using the squared error loss function. and the sampling cost of each observation is 0.25 (in appropriate units). If the total cost of the estimation procedure is equal to the expected loss of the Bayes estimator plus the sampling cost(0.25)n, what is the sample size n for which the total cost will be a minimum?
22. Suppose that XXn form a random sample from a Poisson distribution with unknown mean 0. and the variance of this distribution is to be estimated using the squared error loss function. Determine whether of not the sample variance is an admissible estimator.