> You received this message because you are subscribed to the Google Groups
> "Stanford AI Class" group.
> To post to this group, send email to stanford...@googlegroups.com.
> To unsubscribe from this group, send email to
> For more options, visit this group at
What you work out is the equivalent of rule 1 but for day 2, that is:
Day 2: Sun 0.78 & Rain 0.22.
Rule 4 [R4]: When previous two days sun, then Oooops do not have the
rule, would be even better <-- I don't know why you'd want this
information. You can calculate it fairly easily. It also depends on
whether the first sunny day of the two is day 1 or some other day, so
it's going to get a little messy to state it.
The rule you're applying is conditional probability
P(A|B) = P(A, B) / P(B).
Rearranging this gives you P(A ,B) = P(A|B) * P(B). Not that it's
P(A|B) which is the probability that A happens given that B has
already happened. This is exactly what you're given in your R2 and R3.
R2 is created with R1 in mind since the probabilities give are the
probabilities when you know what happened the day before because R2
probabilities are conditional on R1. It's a bit hard to draw a tree in
an email but I'll try. Note that the probabilities we get on day 2
change dependent on what happened the day before. This is how the
information is 'baked in'.