Skip to content
← All questions

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?

No. Under conditional independence, once the parent's status is known, learning the state of one child node (e.g., probe catching) adds no information about the state of the other child node (e.g., pain). The uncertainty about the second child is fully resolved by the parent's state alone.

Conditions

  • The model exhibits conditional independence given the parent.
  • The parent node's status is known/fixed.

Reasoning, step by step

  1. Fix the state of the parent node.
  2. Observe the distribution of the first child node.
  3. Observe the distribution of the second child node.
  4. 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.

Watch the explanation

Connected concepts

Explore next

Related questions

Meet the concept

↗
Meet the concept

↗
Understand why

↗
Understand why

↗
Know when to use it

↗

Answers are generated from source material and independently checked. Consult the original video or creator if something is unclear.