Skip to content

Question

Math 6010 • Linear Models

Fall 2007 • Question 1

Let \(X_1,X_2,\ldots ,X_n\) and \(Y_1,Y_2,\ldots ,Y_m\) be two independent random samples. We assume that \(X_1,X_2,\ldots ,X_n\) are independent identically distributed exponential \((\lambda )\) random variables and \(Y_1,Y_2,\ldots ,Y_m\) are independent identically distributed exponential \((\mu )\) random variables. We want to test \(H_0:\lambda =\mu \) against the alternative \(H_A:\lambda \ne \mu \).

(i) Find \(T_{m,n}\) the likelihood ratio test. (7 points)

(ii) Prove that \(-2\log T_{m,n}\) converges in distribution under the null hypothesis when \(\min (m,n)\to \infty \). (7 points)

(iii) Show that the likelihood ratio test is asymptotically consistent and prove that the power goes to 1 as \(\min (m,n)\to \infty \). (7 points)

Raw LaTeX

Let \(X_1,X_2,\ldots,X_n\) and \(Y_1,Y_2,\ldots,Y_m\) be two
independent random samples. We assume that \(X_1,X_2,\ldots,X_n\) are
independent identically distributed exponential \((\lambda)\) random variables
and \(Y_1,Y_2,\ldots,Y_m\) are independent identically distributed exponential
\((\mu)\) random variables. We want to test \(H_0:\lambda=\mu\) against the
alternative \(H_A:\lambda\ne\mu\).

(i) Find \(T_{m,n}\) the likelihood ratio test. (7 points)

(ii) Prove that \(-2\log T_{m,n}\) converges in distribution under the null
hypothesis when \(\min(m,n)\to\infty\). (7 points)

(iii) Show that the likelihood ratio test is asymptotically consistent and
prove that the power goes to 1 as \(\min(m,n)\to\infty\). (7 points)