Consider the belief network of Figure 9.38 (page 453), which extends the electrical domain to include an overhead projector. Answer the following questions about how knowledge of the values of some variables would affect the probability of another variable.

(a) Can knowledge of the value of Projector plugged in affect the belief in the value of Sam reading book? Explain.

(b) Can knowledge of Screen lit up affect the belief in Sam reading book? Explain.

(c) Can knowledge of Projector plugged in affect your belief in Sam reading book given that you have observed a value for Screen lit up? Explain.

(d) Which variables could have their probabilities changed if just Lamp works was observed?

(e) If just Power in projector was observed, which variables could have their probabilities changed?