The video [condin1EN] defined the concept of random variables which were “conditionally
independent given some value of another third variable”. Although it may seem
like a useless refinement of interest to very few people, this is not the case: there
are very relevant ideas behind it, and it is the cornerstone of the idea of “state”,
fundamental in multivariable control theory, and “Bayesian networks” in Artificial
Intelligence.
This video complements the “intuitive” examples in the above-mentioned
video with more abstract examples on measurement and process noise, the
concept of state, Markov hypothesis, and the associated Bayesian network
diagrams. It is recommended to watch the video [state2] for more discussions about the
importance of the concept of state and Markov in the modeling of physical
systems.
The video ends presenting some conclusions about the importance of the
concept of conditional independence in scientific methods in general.
Further numerical examples (well, actually particularized to the case of
conditional correlation or lack thereof) are discussed in the video [condnocoEN], recommending
its viewing to consolidate the concepts. The idea is also discussed in the ‘hidden
tiger’ case study that introduces some probability concepts, see video
[tiger4EN].