UGC NET COMPUTER SCIENCE SOLVED PAPERS 2014-16 - UGC NET Computer Science Paper 2 December 2015

31. A data cube C, has n dimensions, and each dimension has exactly p distinct values in the base cuboid. Assume that there are no concept hierarchies associated with the dimensions. What is the maximum number of cells possible in the data cube, C?

  • Option : D
  • Explanation :
    (a) What is the maximum number of cells possible in the base cuboid? pn.
    This is the maximum number of distinct tuples that you can form with p distinct values per dimensions.
    (b) What is the minimum number of cells possible in the base cuboid? p.
    You need at least p tuples to contain p distinct values per dimension. In this case no tuple shares any value on any dimension.
    (c) What is the minimum number of cells possible in the data cube, C? (2n-1)×p+1.
    The minimum number of cells is when each cuboid contains only p cells, except for the apex, which contains a single cell.
    (d) What is the maximum number of cells possible (including both base cells and aggregate cells) in the data cube, C? (p+1)n.
    The argument is similar to that of part (a), but now we have p+1 because in addition to the p distinct values of each dimension we can also choose ∗.
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32. Suppose that from given statistics, it is known that meningitis causes stiff neck 50% of the time, that the proportion of persons having meningitis is 1/50000, and that the proportion of people having stiff neck is 1/20. Then the percentage of people who had meningitis and complain about stiff neck is:

  • Option : B
  • Explanation :
    The computation is based on the simplified Bayes’ formula.
    P{B|A} = (P{A|B}·P{B) / P{A}.
    P{M|S} = probability that a person had meningitis, conditioned by the existence of stiff neck.
    P{S|M} = probability that a person complains about stiff neck, conditioned by the existence of meningitis. = 50%=1/2
    P{S} = proportion of people who complain about stiff neck. = 1/20
    P{M} = proportion of people who had meningitis. = 1/50,000
    Then:
    P{M|S} = (P{S|M}·P{M}) / P{S} =( 1 / 2 x 1 / 50,000 ) / 1 / 20 = 0.0002 = 0.02%
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33. __________ system is market oriented and is used for data analysis by knowledge workers including Managers, Executives and Analysts.

  • Option : B
  • Explanation :
  • OLAP(Online application program) system is market oriented and is used for data analysis by knowledge workers including Managers, Executives and Analysts.
  • OLTP (online transaction processing) is a class of software programs capable of supporting transaction-oriented applications on the Internet.
  • Data system is a term used to refer to an organized collection of symbols and processes that may be used to operate on such symbols
  • A market system is the network of buyers, sellers and other actors that come together to trade in a given product or service
  • So, option (B) is correct.
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34. __________ allows selection of the relevant information necessary for the data warehouse.

  • Option : A
  • Explanation :
  • The Top down view allows selection of the relevant information necessary for the data warehouse.
  • Data Warehouse View contains fact tables and dimension tables
  • Datasource View it shows the the information which was gathered, stored and managed by operational system
  • Business Query View It shows the view of date in warehouse from end user point of view.
  • So, option (A) is correct.
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35. The hash function used in double hashing is of the form:

  • Option : C
  • Explanation :
    h(k, i) = (h1(k) + i * h2(k)) mod m is used in double hashing is of the form. Rest other option does not used in double hashing. So, option (C) is correct.
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