I am having problem solving this exercise. The problem actually comes with a diagram but I do not know and I do not think i can draw it in the forum. The exercise is based on car starting(Heckerman 1995)(adsbygoogle = window.adsbygoogle || []).push({});

Since I can't draw the network diagram here but values of probability are given but first let me define all the variables

B - Battery

G - Gauge

F - Fuel

T - Turnover

S - Start

N - No

Y - Yes

P(B = N) = 0.02

p(F = N) = 0.05

P(G = N|B = Y, F = Y) = 0.04

P(G = N|B = Y, F = N) = 0.97

P(G = N|B = N, F = Y) = 0.10

P(G = N|B = N, F = N) = 0.99

P(T = N|B = Y) = 0.03

P(T = N|B = N) = 0.98

P(S = N|T = Y, F = Y) = 0.01

P(S = N|T = Y, F = N) = 0.92

P(S = N|T = N, F = Y) = 1.0

P(S = N|T = N, F = N) = 1.0

It was asked to calculate p(F = N|S = N)

Im thinking of Bayesian but I got stuck somewhere so I think it is the wrong approach since S depend on F and T NOT F alone.

Im thinking of the other approach and came up with an expression

P(F = N|S = N) = P(S = N|F = N)/P(F)

= P(S = N, B, G, T|F = N)/P(F)

But I am not sure how to compute and put the figures together.

Any input/help is appreciated. Thank you

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# Belief network problem

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