Daphne Koller

Wrapup

BNs vs MNs

ProbabilisticGraphicalModels

Representation

Consider representing a given P using a graphical model. Which of the following is correct?

P can always be represented as a BN but maybe not an MN.

P always can be represented as an MN but maybe not a BN.

P can always be represented both as a BN and as an MN.

It’s possible that P can be represented as neither a BN nor an MN.

Consider representing a given P using a graphical model, where our goal is to capture I(P) exactly. Which of the following is correct?

I(P) can always be represented as a BN but maybe not an MN.

I(P) always can be represented as an MN but maybe not a BN.

I(P) can always be represented both as a BN and as an MN.

It’s possible that I(P) can be represented using neither a BN nor an MN.

Daphne Koller

Bayes Net as Gibbs DistributionIntelligenceDifficulty

Grade

Letter

SAT

IntelligenceDifficulty

Grade

Letter

SAT

IntelligenceDifficulty

Grade

Letter

SAT

IntelligenceDifficulty

Grade

Letter

SAT

IntelligenceDifficulty

Grade

Letter

SAT

Which of the following undirected graphs is the minimal I-map for the distribution P encoded by the BN on the right?

IntelligenceDifficulty

Grade

Letter

SAT

Daphne Koller

What Do We Lose?

IntelligenceDifficulty

Grade

Letter

SAT

IntelligenceDifficulty

Grade

Letter

SAT

BD

C

A

BD

C

AConsider a distribution P represented perfectly by the MN H. Which of the following are true? Mark all that apply.

G is a minimal I-map for P

H G

G is an I-map for P but is not minimal G is not an I-map for P because G is not an I-map for P because

Daphne Koller

What Do We Lose?

BD

C

A

Daphne Koller

Which Should I Use?