3.22 Let the observations resulting from an experiment be xn,n=1,2,,N. Assume that they are independent and that they originate from a Gaussian PDF N(,2). Both the mean and the variance are unknown. Prove that the ML estimates of these quantities are given by ^ML=N1n=1Nxn,^ML2=N1n=1N(xn^ML)2. 3.23 Let the observations xn,n=1,2,,N, come from the uniform distribution p(x;)={1,0,0x,otherwise. Obtain the ML estimate of . 3.24 Obtain the ML estimate of the parameter >0 of the exponential distribution p(x)={exp(x),0,x0x