Under conditional independence in a common-parent model, does learning the state of one child node provide additional information about the other child node if the parent is known?
Conditions
- The model exhibits conditional independence given the parent.
- The parent node's status is known/fixed.
Reasoning, step by step
- Fix the state of the parent node.
- Observe the distribution of the first child node.
- Observe the distribution of the second child node.
- Verify that the probability of the second child does not change when the first child's state is revealed.
Example
The script states: 'Under conditional independence, learning catch adds no information about pain once cavity is known.'
Common misconceptions
- Believing that because the children are correlated marginally, they must remain informative about each other even when the parent is known.
- Confusing conditional independence with marginal independence.
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