We have random variable Y1,Y2,,Yn satisfying Yn=xi+i,i=1,2,,n Where x1,x2,,xn are fixed constants and 1,,n are iid N(0,2),2 unknown a) what's the 2-dimensional sufficient statistics for (,2) b) find the MLE of and show that it is the unbiased estimator of . Find distribution MLE of . c) show that yi/xi is an unbiased estimator of . d) calculate exact variance of Yyi/xi and compare it to the variance of the MLE