This set of Data Mining Multiple Choice Questions & Answers (MCQs) focuses on “Measuring Data Similarity and Dissimilarity”.
1. Which of the following is not a proximity measure?
a) Similarity measures
b) Dissimilarity measures
c) Distance measures
d) Probability measures
View Answer
Explanation: The proximity measures are used to evaluate the similarity and dissimilarity between the two objects. Similarity measures, dissimilarity measures and distance measures are the commonly used proximity measures.
2. The value zero for a similarity measure indicates no similarity between two objects.
a) True
b) False
View Answer
Explanation: The similarity measures are used to find the degree of similarity between the two objects under consideration. A value zero for a similarity measure indicates that there is no similarity between the two objects.
3. Which of the following is true if the value of a dissimilarity measure is zero for two objects?
a) The two objects are very similar
b) The two objects are very dissimilar
c) The two objects are moderately dissimilar
d) The two objects are moderately similar
View Answer
Explanation: The dissimilarity measures evaluate the level of dissimilarity between the two objects under consideration. A value zero for a dissimilarity measure indicates that the two objects are very similar.
4. A data matrix can also be referred to as _____
a) Object by attribute structure
b) Attribute by object structure
c) Hierarchical object structure
d) Number by number structure
View Answer
Explanation: A data matrix is used to store the values of the data objects. It is also referred to as an object by attribute structure. The rows of the data matrix correspond to the data objects and the columns correspond to the attributes of an object.
5. Which of the following refers to the dissimilarity matrix of objects?
a) Attribute by object structure
b) Object by object structure
c) Clustered group structure
d) Attribute by attribute structure
View Answer
Explanation: A dissimilarity matrix is used to store the values of dissimilarity between the objects. It is also referred to as the object by object structure. Each row and column corresponds to an object and the dissimilarity values between the pair of objects are stored.
6. Data matrix is a two mode matrix.
a) True
b) False
View Answer
Explanation: A data matrix is used to store the data values. The rows correspond to the objects and the columns correspond to the attributes. Thus, it is made up of two entities and hence, known as a two mode matrix.
7. Which of the following is true about the dissimilarity matrix?
a) It is a one mode matrix
b) It is a two mode matrix
c) It is a three mode matrix
d) It is a four mode matrix
View Answer
Explanation: In a dissimilarity matrix, both rows and columns correspond to the data objects and the dissimilarity between the pair of objects is stored. Since it is made up of only one entity, the dissimilarity matrix is also referred to as a one mode matrix.
8. Which of the following is true for nominal attributes?
a) Similarity = 1 – Dissimilarity
b) Similarity = 1 + Dissimilarity
c) Similarity = 2 * Dissimilarity
d) Similarity = 2 – Dissimilarity
View Answer
Explanation: Measures of similarity and dissimilarity can often be derived from each other if one of them is known. In case of nominal data, the relation, Similarity = 1 – Dissimilarity, is found to be valid.
9. If n be the number of attributes of an object, m be the matches when the state of two objects is same, then which of the following is true in the case of dissimilarity of nominal attributes?
a) Dissimilarity = (n – m)/n
b) Dissimilarity = (n + m)/n
c) Dissimilarity = (n * m)/n
d) Dissimilarity = (n – m)/m
View Answer
Explanation: In nominal data, the measures of dissimilarity represent the degree of difference between the data points. The relation, Dissimilarity = (n – m)/n, is valid for nominal data, where n is the number of attributes of the object and m is the number of state matches for the attributes of the objects.
10. If for an object, n be the number of attributes, m be the number of matches in case the state of two objects is same, then which of the following is true regarding the similarity of nominal attributes?
a) Similarity = n/m
b) Similarity = m/n
c) Similarity = 2 * m * n
d) Similarity = m * n
View Answer
Explanation: In case of nominal data, the similarity measures represent the level of alikeness between the data objects. The relation, Similarity = m/n, is valid for the similarity between the objects in nominal data, where m is the number of state matches for the attributes of the objects and n is the number of attributes of the object.
Sanfoundry Global Education & Learning Series – Data Mining.
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