DATABASE FUNDAMENTALS
DATA WAREHOUSING AND DATA MINING
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Question
[CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
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Total number of transactions containing A
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Total Number of transactions not containing A
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Number of transactions containing A / Total number of transactions
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Number of transactions not containing A / Total number of transactions
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Detailed explanation-1: -1) Correct answer is option(a): Number of transactions containing A/ total number of transactions. Support in data mining means how frequently an item appears in a data.
Detailed explanation-2: -The support of an association rule is the percentage of groups that contain all of the items listed in that association rule. The percentage value is calculated from among all the groups that were considered.
Detailed explanation-3: -The Apriori algorithm is used for mining frequent itemsets and devising association rules from a transactional database. The parameters “support” and “confidence” are used. Support refers to items’ frequency of occurrence; confidence is a conditional probability. Items in a transaction form an item set.
Detailed explanation-4: -Support refers to how often a given rule appears in the database being mined. Confidence refers to the amount of times a given rule turns out to be true in practice. A rule may show a strong correlation in a data set because it appears very often but may occur far less when applied.
Detailed explanation-5: -Support = (X+Y) total – It is interpreted as fraction of transactions that contain both X and Y.