Question

1. Suppose that these three-item sets (A BC), (A B D), (A C D), (A CE), (A D E) satisfy the minimum support. Discuss whether these four-item sets can be considered as frequent item sets 3. Using the table below, create frequent 3-item sets using minimum support of 3. Phone Tablet Laptop Desktop PC Hard Disk Flash Disk No No Yes 0 Yes 0 Yes No No Yes Yes Yes Yes 0 0 Yes Yes No No No Yes Yes No No No Yes Yes 0 0 0

Answer 1

1)

Note that an itemset is said to be frequent if all of its subset are frequent

Consider all the possible 4 itemsets -

(a, b, c, d) - since (b, c, d) is not a frequent itemset hence (a, b, c, d) cannot be a frequent itemset

(a, b, c, e) - since (b, c, e) is not a frequent itemset hence (a, b, c, e) cannot be a frequent itemset

(a, b, d, e) - since (b, d, e) is not a frequent itemset hence (a, b, d, e) cannot be a frequent itemset

(a, c, d, e) - since (c, d, e) is not a frequent itemset hence (a, c, d, e) cannot be a frequent itemset

Similarly you can check all the 4 itemsets Since all of its possible 3 itemsets are not frequent hence none of the 4 itemsets are frequent

3)

Consider Phone as a, Tablet as b and so on

List all the attributes as a pair for which value is yes

For tuple 1 - (b, d, e)

For tuple 2 - (a, d)

For tuple 3 - (a, b, d, f)

For tuple 4 - (c, d, f)

For tuple 5 - (b, d, e, f)

For tuple 6 - (a, c, e, f)

For tuple 7 - (a, b, f)

For tuple 8 - (a, b, c, f)

For tuple 9 - (c, e)

For tuple 10 - (b, d)

For tuple 11 - (a, b, c, f)

For tuple 12 - (a, c, f)

Since minimum support count is 3

Hence find all the 3-itemsets whose frequency >= 3

Answer) (a, b, f), (a, c, f)

I have tried to explain it in very simple language and I hope that i have answered your question satisfactorily.Leave doubts in comment section if any.