Let $X_{1}, X_{2}$ be a random sample of size $n=2$ from the distribution having pdf $f(x ; \theta)=(1 / \theta) e^{-x / \theta}, 0<x<\infty$, zero elsewhere. We reject $H_{0}: \theta=2$ and accept $H_{1}: \theta=1$ if the observed values of $X_{1}, X_{2}$, say $x_{1}, x_{2}$, are such that
$$
\frac{f\left(x_{1} ; 2\right) f\left(x_{2} ; 2\right)}{f\left(x_{1} ; 1\right) f\left(x_{2} ; 1\right)} \leq \frac{1}{2}
$$
Here $\Omega=\{\theta: \theta=1,2\}$. Find the significance level of the test and the power of the