(a) What is the confidence for the rules ∅ → A and A → ∅?
(b) Let c1, c2, and c3 be the confidence values of the rules {p} → {q}, {p} → {q, r}, and {p, r} → {q}, respectively. If we assume that c1, c2, and c3 have different values, what are the possible relationships that may exist among c1, c2, and c3? Which rule has the lowest confidence?
(c) Repeat the analysis in part (b) assuming that the rules have identical support. Which rule has the highest confidence?
(d) Transitivity: Suppose the confidence of the rules A → B and B → C are larger than some threshold, minconf. Is it possible that A → C has a confidence less than minconf?