0
$\begingroup$

Say I have a simple Bayes Net that appears like that in the picture and am giving the following probabilities:

$P(y|x) = 0.5$

$P(z|x)=0.4$

$P(y|\bar{x})=0.8$

$P(z|\bar{x}) = 0.9 $

Bayes Net

How would I calculate the following, or is it not possible to calculate them? I think I need to know $P(x)$ to be able to calculate them:

$P(y)$

$P(x|y \land z)$

$P(x|y)$

$\endgroup$
0
$\begingroup$

How would I calculate the following, or is it not possible to calculate them? I think I need to know P(x) to be able to calculate them:

Yes.

$P(y)=P(x)P(y\mid x)+P(\bar x)P(y\mid\bar x)$

$P(x\mid y,z) = \dfrac{P(x)P(y\mid x)P(z\mid x)}{P(x)P(y\mid x)P(z\mid x)+P(\bar x)P(y\mid\bar x)P(z\mid\bar x)}$

$P(x\mid y)=\dfrac{P(x)P(y\mid x)}{P(y)}$

$\endgroup$

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.