Data Mining | Week 2

Data Mining Week 2 Answers

link: Data Mining Week 2 (nptel.ac.in)

Q1. If a store has N items, the number of possible itemsets is

a. 2N-1

b. 2^N-1

c. N/2

d. N-1

Q2. An association rule is valid if it satisfies:

a. Support criteria

b. Confidence criteria

c. Both support and confidence criteria

d. None of these

Q3. An itemset is frequent if it satisfies the:

a. Support criteria

b. Confidence criteria

c. Both support and confidence criteria

d. None of these

Q4. Which of the following property is used by the apriori algorithm:

a. Positive definiteness property of support

b. Positive semidefiniteness property of support

c. Monotone property of support

d. Antimonotone property of support

Q.5. Consider three itemsets I1={bat, ball, wicket}, I2={bat, ball}, I3={bat}. Which of the following statements are correct?

a. support(I1) > support(I2)

b. support(I2) > support(I3)

c. both statements A and B

d. none of the statements A and B

For questions 6-10, consider the following small database of four transactions. The minimum support is 60% and the minimum confidence is 80%.

Trans_id              Itemlist

T1                          {F, A, D, B}

T2                          {D, A, C, E, B}

T3                          {C, A, B, E}

T4                          {B, A, D}

Q6. The 1-itemsets that satisfy the support criteria are:

a. {A}, {B}, {C}, {D}

b. {A}. {B}, {C}

c. {A}, {B}

d. None of these

Q7. The 2-itemsets that satisfy the support criteria are:

a. {BC}, {BE}, {CE}, {AE}

b. {AB}. {BD}, {AD}

c. {AE}, {BC}

d. {BC}

Q8. The 3-itemsets that satisfy the support criteria are:

a. {ABC}, {ABE}, {BCD}, {ACD}

b. {ABE}. {BCD}, {ACD}

c. {ABE}, {BCD}

d. {ABD}

Q9. Which of the following is NOT a valid association rule?

a. A -> B

b. B -> A

c. A -> D

d. D -> A

Q10. Which of the following is NOT a valid association rule?

a. A -> DB

b. D -> AB

c. AD -> B

d. DB -> A