Information Gain in Decision Trees
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Questions and Answers

What is the entropy of a group in which all examples belong to the same class?

  • 0 (correct)
  • 1
  • Undefined
  • Maximum
  • What is the entropy of a group with 50% in either class?

  • 0.5
  • Undefined
  • 1 (correct)
  • 0
  • Which of the following best describes the goal of information gain?

  • To determine the most useful attribute for discriminating between classes (correct)
  • To calculate the average message length of a Huffman code
  • To minimize the uncertainty in the class distribution
  • To maximize the uncertainty in the class distribution
  • In the Huffman coding example provided, what is the average message length?

    <p>1.75</p> Signup and view all the answers

    What is the relationship between entropy and conditional entropy?

    <p>Entropy is the sum of conditional entropy and mutual information</p> Signup and view all the answers

    Which of the following is a key property of decision trees?

    <p>They greedily optimize for information gain at each split</p> Signup and view all the answers

    What does impurity measure in a group of examples?

    <p>The level of randomness or disorder in the group</p> Signup and view all the answers

    Which coding scheme assigns bits based on -log2P(X=i) to encode a message X?

    <p>David Huffman's code</p> Signup and view all the answers

    What does entropy measure for a random variable X?

    <p>The expected number of bits needed to encode a randomly drawn value of X</p> Signup and view all the answers

    In decision trees, what does Information Gain help determine?

    <p>The optimal split attribute for classification</p> Signup and view all the answers

    What is Mutual Information used for in machine learning?

    <p>To evaluate feature importance by measuring the relationship between variables</p> Signup and view all the answers

    What is the purpose of Information Gain in the context of decision trees?

    <p>To determine the order of attributes in the nodes of a decision tree</p> Signup and view all the answers

    What is the formula for calculating the entropy of a random variable X?

    <p>$H(X) = -\sum_{i=1}^{n} P(x_i) \log_2 P(x_i)$</p> Signup and view all the answers

    What is the relationship between Information Gain and Mutual Information?

    <p>Information Gain is the same as Mutual Information</p> Signup and view all the answers

    What is the purpose of calculating the conditional entropy in the context of decision trees?

    <p>To calculate the entropy of a subset of the data after splitting on an attribute</p> Signup and view all the answers

    In the example shown, what is the value of the Information Gain when splitting on the attribute used in the root node?

    <p>0.38</p> Signup and view all the answers

    Which of the following statements about entropy and information gain is true?

    <p>Entropy and information gain are inversely related</p> Signup and view all the answers

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