长城脚下的“代理家长”：目送孩子们飞向山外广阔天地
That’s it! If you take this equation and you stick in it the parameters θ\thetaθ and the data XXX, you get P(θ∣X)=P(X∣θ)P(θ)P(X)P(\theta|X) = \frac{P(X|\theta)P(\theta)}{P(X)}P(θ∣X)=P(X)P(X∣θ)P(θ), which is the cornerstone of Bayesian inference. This may not seem immediately useful, but it truly is. Remember that XXX is just a bunch of observations, while θ\thetaθ is what parametrizes your model. So P(X∣θ)P(X|\theta)P(X∣θ), the likelihood, is just how likely it is to see the data you have for a given realization of the parameters. Meanwhile, P(θ)P(\theta)P(θ), the prior, is some intuition you have about what the parameters should look like. I will get back to this, but it’s usually something you choose. Finally, you can just think of P(X)P(X)P(X) as a normalization constant, and one of the main things people do in Bayesian inference is literally whatever they can so they don’t have to compute it! The goal is of course to estimate the posterior distribution P(θ∣X)P(\theta|X)P(θ∣X) which tells you what distribution the parameter takes. The posterior distribution is useful because
。搜狗输入法跨平台同步终极指南：四端无缝衔接是该领域的重要参考
It comes shortly after the defence secretary reiterated president Donald Trump’s threat that if Iran does anything to prevent the flow of oil in the strait of Hormuz, it will be hit “twenty times harder”.
Артём Верейкин (Ночной выпускающий редактор)