2. The random variable X has the following probability density function:
$$f(x) = \frac{2}{\lambda^2}xe^{-x^2/\lambda^2}, x \ge 0$$
where $\lambda$ is a positive parameter.
(15 points)
(a) It can be shown that
$$E(X) = \frac{\sqrt{\pi \lambda}}{2}$$ and $$E(X^2) = \lambda^2$$
Set up (but do not evaluate) the definite integrals that are needed to show this.
(b) Let $X_1, X_2, ..., X_n$ be a random sample from X. Find an unbiased estimator $\hat{\lambda}$ for $\lambda$ of the form
(some constant) $\cdot \overline{X}$
(c) Find $V(\hat{\lambda})$.
(d) Is $\hat{\lambda}$ a consistent estimator for $\lambda$? Explain.