Cho A, B, C, D là các item và A-->BC là luật kết hợp thỏa mãn độ hỗ trợ tối thiểu Min_Sup và độ tin cậy tối thiểu Min_Conf. Hãy cho biết luật kết hợp nào sau đây chắc chắn thỏa mãn Min_Sup và Min_Conf mà không cần phải tính độ hỗ trợ và độ tin cậy:
Trả lời:
Đáp án đúng: A
Given the association rule A-->BC holds with minimum support (Min_Sup) and minimum confidence (Min_Conf), we need to determine which of the following rules is guaranteed to hold. Since A-->BC holds, we know Sup(A ∪ BC) >= Min_Sup and Conf(A-->BC) = Sup(A ∪ BC) / Sup(A) >= Min_Conf. Therefore, Sup(A ∪ B ∪ C) >= Min_Sup.
A) AB-->C: To determine if AB-->C holds, we need to check if Sup(AB ∪ C) >= Min_Sup and Conf(AB-->C) = Sup(AB ∪ C) / Sup(AB) >= Min_Conf. We know Sup(A ∪ B ∪ C) >= Min_Sup. However, Sup(AB) could be very small, making the confidence low. Also, we don't know if Sup(AB ∪ C) >= Min_Sup.
B) A-->D: This rule involves item D, which is not in the original rule A-->BC. Therefore, we can't determine if this rule holds.
C) ABD-->C: This rule requires Sup(ABD ∪ C) >= Min_Sup and Conf(ABD-->C) = Sup(ABD ∪ C) / Sup(ABD) >= Min_Conf. Similar to option A, the addition of D can affect the support. Also, because Sup(ABD) is likely smaller than Sup(A), the Confidence may be greater or smaller depending on whether Support (ABCD) is smaller by a lot
D) D-->C: This rule involves item D, which is not in the original rule A-->BC. Therefore, we can't determine if this rule holds.
None of the options can be guaranteed to be correct.
