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Choose an option to check your answer.
A.
It prunes all supersets containing that itemset
B.
It generates every possible superset
C.
It converts it to a class label
D.
It raises its support count
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Correct Answer: A. It prunes all supersets containing that itemset
Explanation:
By anti-monotonicity, no superset of an infrequent set can be frequent.
Pruning avoids unnecessary support counting.
Choose an option to check your answer.
A.
Removing items always decreases support
B.
Support and confidence are identical
C.
All itemsets have positive lift
D.
Adding items to an itemset cannot increase its support
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Correct Answer: D. Adding items to an itemset cannot increase its support
Explanation:
A transaction containing a larger itemset must contain all its subsets.
Therefore a superset's support is never greater.
Choose an option to check your answer.
A.
Every superset of an infrequent itemset is frequent
B.
Confidence always decreases with rule length
C.
Every subset of a frequent itemset must also be frequent
D.
All frequent itemsets have equal support
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Correct Answer: C. Every subset of a frequent itemset must also be frequent
Explanation:
The Apriori property follows from support anti-monotonicity.
An itemset cannot occur more often than any of its subsets.
Choose an option to check your answer.
A.
Using no support threshold
B.
Searching only for patterns that satisfy user-specified conditions
C.
Mining only one-itemsets
D.
Replacing transactions with clusters
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Correct Answer: B. Searching only for patterns that satisfy user-specified conditions
Explanation:
Constraints can restrict items, rule length, aggregate values, or business conditions.
They reduce search and focus the output on relevant patterns.
Choose an option to check your answer.
A.
Lift
B.
Antecedent length
C.
Transaction ID
D.
Support count of X alone
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Correct Answer: A. Lift
Explanation:
Lift compares rule confidence with the consequent's baseline support.
A value above one indicates improvement over the baseline frequency.
Choose an option to check your answer.
A.
The rule is strongly predictive
B.
The consequent is rare
C.
The itemset is invalid
D.
The items are common but nearly independent
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Correct Answer: D. The items are common but nearly independent
Explanation:
High support reflects frequent co-occurrence in absolute terms.
Lift near one shows the co-occurrence is close to what marginal popularity predicts.
Choose an option to check your answer.
A.
Rules contain no items
B.
Support is always zero
C.
Co-occurrence can arise from confounding, common popularity, or chance
D.
Confidence measures randomized experiments
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Correct Answer: C. Co-occurrence can arise from confounding, common popularity, or chance
Explanation:
Association measures observational dependence rather than intervention effects.
Business context and causal analysis are needed before claiming causation.
Choose an option to check your answer.
A.
A rule contains no antecedent
B.
Multiple rules convey essentially the same information
C.
A rule has confidence above one
D.
The dataset has duplicate rows only
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Correct Answer: B. Multiple rules convey essentially the same information
Explanation:
Association mining can generate many overlapping rules from related itemsets.
Pruning and concise representations improve interpretability.
Choose an option to check your answer.
A.
A single support threshold may miss meaningful patterns involving infrequent items
B.
Rare items always have high confidence
C.
Infrequent items cannot appear in rules
D.
Rare items make transactions identical
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Correct Answer: A. A single support threshold may miss meaningful patterns involving infrequent items
Explanation:
Different items may have very different baseline frequencies.
Multiple minimum supports or specialized methods can better handle rare but important items.
Choose an option to check your answer.
A.
It always increases false positives
B.
It makes every itemset frequent
C.
It prevents transaction scanning
D.
It can miss rare but important associations
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Correct Answer: D. It can miss rare but important associations
Explanation:
Some valuable patterns, such as rare adverse events, naturally have low support.
An excessive threshold filters them out.
Choose an option to check your answer.
A.
It guarantees no itemsets are found
B.
It makes confidence undefined for every rule
C.
It can produce an enormous number of patterns, many of limited value
D.
It removes rare patterns
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Correct Answer: C. It can produce an enormous number of patterns, many of limited value
Explanation:
Lower support allows many combinations to qualify as frequent.
This increases computation and the burden of interpreting results.
Choose an option to check your answer.
A.
To identify frequent itemsets before support counting
B.
To filter rules that do not predict the consequent reliably enough
C.
To remove long transactions
D.
To normalize numeric attributes
Show Answer
Correct Answer: B. To filter rules that do not predict the consequent reliably enough
Explanation:
Confidence evaluates conditional rule strength.
Rules below the chosen threshold are excluded from the final set.