exam 3 - chapter 9

Question 1

Classification Model

Answer 1

Classification Model
• Classifies objects into a set of pre-specified object classes (or categories) based on the values of relevant object attributes (features) and objects’class labels

Question 2

Oi:

Answer 2

Oi: contains relevant attribute values
and class labels

Question 3

Classes X, Y and Z are

Answer 3

Classes X, Y and Z are pre-determined

Question 4

Benefit of Classification

Answer 4

Benefit of Classification
• Identifying the class by a single or a small number of data attributes (e.g., gender, age) is manageable by human decision makers, but not when the number of attributes or the number of instances is large.
• Estimating/predicting the class or category of action recipient supports time and cost-effective decision making.
The class will be or is “X” The class will be or is likely to be “X” 3

Question 5

Motivating Business Questions, Costs and Benefits

• How do we identify mobile phone service customers who are likely to churn

Answer 5

Motivating Business Questions, Costs and Benefits
• How do we identify mobile phone service customers who are likely to churn (switch to another carrier)?
• Churn or not: classes of customers
• Which customers: identified by customers’ attribute-value information –e.g., age, income, gender, services subscribed, service utilization, etc.

Question 6

Motivating Business Questions, Costs and Benefits

• So what? (churn)

Answer 6

• So what?
  
  • Potential actions –increase or decrease customer service for customers likely to churn
  • Costs –increased service cost or loss of loyal customers
  • Benefits -reduced churn rate or service cost

Question 7

Motivating Business Questions, Costs and Benefits

• How do we find customers who are likely to repurchase?

Answer 7

Motivating Business Questions, Costs and Benefits
• How do we find customers who are likely to repurchase?
• Repurchase or not: classes of customers
• Which customers: identified by customers’ attributes-value information –e.g., recency, frequency and monetary amount of prior purchases (RFM approach)

Question 8

Motivating Business Questions, Costs and Benefits

• so what? (repurchase)

Answer 8

Motivating Business Questions, Costs and Benefits
• so what? (repurchase)
• Potential actions -Target emailing potential repurchase customers; more customer services; offer coupons/incentives
• Costs –Cost of targeting and cost of losing re-purchase transactions
• Benefits –Increase repurchase amounts

Question 9

look at charts, formula on slides

Answer 9

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Question 10

Evaluation Metrics

• Accuracy is the _

Answer 10

Evaluation Metrics
• Accuracy is the overall correctness of the model and is calculated as the sum of correct classifications divided by the total number of classifications.

Question 11

Decision Tree Induction
• The learning of decision trees from ___
[3]

Answer 11

Decision Tree Induction
• The learning of decision trees from class-labeled training data.
     • Internal node is a test on the attribute.
     • Branch is the outcome.
     • Leaf node holds the
class label.
     • Most are binary but some
are none binary.

Question 12

Decision Tree

- mapping principle:

Answer 12

Decision Tree

• Mapping Principle:Recursively partition the data set so that the subsets contain “pure”data