General EM Method

Define likelihood function $Q(h' \,|\, h)$ which calculates $Y = X \union Z$ using observed $X$ and current parameters $h$ to estimate $Z$ \[ Q(h' \,|\, h) \leftarrow E[ \ln P(Y \,|\, h') \,|\, h, X ] \]

E step: Calculate $Q(h'\,|\,h)$ using the current hypothesis $h$ and the observed data $X$ to estimate the probability distribution over $Y$. \[ Q(h' \,|\, h) \leftarrow E[ \ln P(Y \,|\, h') \,|\, h, X ] \]
M step: Replace hypothesis $h$ by the hypothesis $h'$ that maximizes this $Q$ function. \[ h \leftarrow \argmax_{h'} Q(h' \,|\, h) \]