Consider the pdf \(f(x;\theta )=\theta x^{-(\theta +1)}\) (\(x\geq 1\)). Let \(X_i\) be a random sample of size \(n\) with pdf \(f(x;\theta _1)\). Let \(Y_i\) be a random sample of size \(m\) with pdf \(f(x;\theta _2)\). The two sets of random variables are independent. We wish to test \[ H_0:\theta _1=\theta _2 \quad \text {against}\quad H_a:\theta _1\ne \theta _2. \]
6a) (5 points) If one considers just the \(X\)-data, find the MLE \(\hat \theta _1\).
6b) (5 points) Derive a formula for the critical region obtained using the generalized likelihood ratio method.