title: 斯坦福-随机图模型-week2.4
tags: note
notebook: 6- 英文课程-9-Probabilistic Graphical Models 1: Representation
---
斯坦福-随机图模型-week2.4
习题
第 1 个问题
Causal Influence. Consider the CPD below. What is the probability that E=e0 in the following graph, given an observation A=a0,B=b0,C=c1,D=d1? Note that for the pairs of probabilities that make up the leaves, the probability on the left is the probability of e0, and the probability on the right is the probability of e1.
0.6
正确回答
This is the probability that is reached when following the tree down the appropriate branches.第 2 个问题
正确
1 / 1 分
2。第 2 个问题
Independencies with Deterministic Functions. In the following Bayesian network, the node B is a deterministic function of its parent A. Which of the following is an independence statement that holds in the network? You may select 1 or more options.
(A⊥B∣C,D)
未选择的是正确的 (A⊥D∣B)
正确
Given B, there is no active trail between A and D therefore, they are conditionally independent.(C⊥D∣B)
正确
Since B is given and is the only parent of C and of D, C and D are independent.(B⊥D∣C)
未选择的是正确的 第 3 个问题
正确
1 / 1 分
3。第 3 个问题
Independencies in Bayesian Networks. For the network in the previous question, let B no longer be a deterministic function of its parent A. Which of the following is an independence statement that holds in the modified Bayesian network? You may select 1 or more options.
(B⊥D∣C)
未选择的是正确的 (C⊥D∣A)
未选择的是正确的 (A⊥D∣B)
正确
The only active trail from A to D passes through B, and there are no V-structures between A and D, so observing B makes A and D independent.(A⊥D∣C)
未选择的是正确的 第 4 个问题
正确
1 / 1 分
4。第 4 个问题
Context-Specific Independencies in Bayesian Networks. Which of the following are context-specific independences that do exist in the tree CPD below? (Note: Only consider independencies in this CPD, ignoring other possible paths in the network that are not shown here. You may select 1 or more options.)
(E⊥cC∣b0,d0)
未选择的是正确的 (E⊥cD∣a0)
未选择的是正确的
(E⊥cD∣b1)
正确
A variable X is independent of E given conditioning assignments z¯ if all paths consistent with z¯ traversed in the tree CPD reach a leaf without querying X. This is true for this option.(E⊥cD,B∣a1)
正确
A variable X is independent of E given conditioning assignments z¯ if all paths consistent with z¯ traversed in the tree CPD reach a leaf without querying X. This is true for this option.
