Data Mining | Week 4

Data Mining Week 4 Answers

Q1. Which of the following statement is true about Bayes classifier?

(A) It always provides zero error when class distributions are known
(B) It always provides the lowest possible error when class distributions are known
(C) It may not always provide the lowest possible error when class distributions are known
(D) It always provides the lowest possible error when class distributions are estimated

Q2. Let A be an example, and C be a class. The probability P(C|A) is known as:

(A) Apriori probability
(B) Aposteriori probability
(C) Class conditional probability
(D) None of these

Q3. Let A be an example, and C be a class. The probability P(C) is known as:

(A) Apriori probability
(B) Aposteriori probability
(C) Class conditional probability
(D) None of these

Q4. Consider a binary classification problem with two classes C1 and C2. Class labels of ten other training set instances sorted in increasing order of their distance to an instance x are as follows: {C1, C2, C1, C2, C2, C2, C1, C2, C1, C2}. How will a K=3 nearest neighbor classifier classify x

(A) There will be a tie
(B) C1
(C) C2
(D) Not enough information to classify

Q5. According to the following graph, what should be the appropriate value of K if KNN algorithm is used?

(A) 5
(B) 10
(C) 15
(D) 20

Q6. Which of the following will be Euclidean Distance between the two data point A(1,3) and B(2,3)?

(A) 1
(B) 2
(C) 4
(D) 8

Q7. Which of the following will be Manhattan Distance between the two data point A(1,3) and B(2,3)?

(A) 1
(B) 2
(C) 4
(D) 8

Q8. You are given the following set of training examples where x and y are the two inputs and Class is the target. What would be the target class of a data point x=1, y=1 using Euclidean distance in 3-NN?

(A) Class +
(B) Class –
(C) None of the above
(D) Can’t be determined.

Q9. What would be the class if 7-NN is used?

(A) Class +
(B) Class –
(C) None of the above
(D) Can’t be determined.

Q10. In the following figure you are given the distances between the two points A(x1,y1) and B(x2,y2).

(A) Left: Manhattan distance and Right: Euclidean Distance
(B) Left: Euclidean distance and Right: Manhattan distance
(C) Both are Euclidean distance
(D) None of the above

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