Answer consider the following pair of rules and their

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Answer: Consider the following pair of rules and their con±dence levels : No. Rule Conf. 1. persons P , 10000 < P . salary 20000 P . credit = good 60% 2. persons P , 20000 < P . salary 30000 P . credit = good 90% The new rule has to be assigned a con±dence-level which is between the con±dence-levels for rules 1 and 2. Replacing the original rules by the new rule will result in a loss of con±dence-level information for classifying persons, since we cannot distinguish the con±dence levelsof perople earning between 10000 and 20000 from those of people earning between 20000 and 30000. Therefore we can combine the two rules without loss of information only if their con±dences are the same. 20.4 Consider the schema depicted in ²igure 20.2. Give an SQL query to summarize sales numbers and price by store and date, along with the hierarchies on store and date. Answer: query: select store-id , city , state , country , date , month , quarter , year , sum ( number ), sum ( price ) from sales , store , date where sales.store-id = store.store-id and sales.date = date.date groupby rollup ( country , state , city , store-id) , rollup ( year , quarter , month , date ) 20.5 Consider a classi±cation problem where the classi±er predicts whether a person has a particular disease. Suppose that 95% of the people tested
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Answer Consider the following pair of rules and their...

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