Question 61
Which of the following statements regarding EXPECTATION-MAXIMIZATION (EM) for GMMs are CORRECT?
In the E-step, the current parameters are used to compute posterior responsibilities gamma_ik for each data point and component. The M-step then updates means, covariances, and mixing weights by maximizing the expected complete-data log-likelihood. EM monotonically increases (or leaves unchanged) the observed-data log-likelihood under the standard conditions, but it is not guaranteed to find the global optimum.