Let $\mathbf{X}=(X, Y)$ be a jointly Gaussian random vector with zero means, unit variances, and unknown correlation coefficient $\rho$. Consider a random sample of $n$ such vectors.
(a) Show that the ML estimator for $\rho$ involves solving a cubic eqation.
(b) Show that Problem 8.23 gives the ML estimator if the mean and variances are unknown.
(c) Repeat 5 trials of the following: Generate a sample of 100 observations of the pairs of zero-mean, unit-variance Gaussian random variables and estimate $\rho$. using parts a and b for the cases: $\rho=0.5, \rho=0.9$, and $\rho=0$.