I have a sample $X_1, \dots, X_n \sim Bern(p)$ and need to test $$H_0: p = p_0\\H_1: p < p_0$$ using the likelihood ratio test. I know how to do it for the two-sided alternative: we should calculate $$LR = 2 (\ln L(x, \hat{p}^{ML}) - \ln L(x, p_0))$$ where $L(x, \cdot)$ is a likelihood function and $\hat{p}^{ML} = \bar{x}$. And then use the fact that $$LR \underset{H_0}{\sim} \chi^2(1)$$ to test the hypothesis. But how should I incorporate the fact that the alternative now is $p < p_0$? Should the distribution of $LR$ change in this case?
Would be very grateful for any help!