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Questions and Answers
What does Wolpert's 'no free lunch theorems' imply about learning methods?
What does Wolpert's 'no free lunch theorems' imply about learning methods?
- There is always a superior learning method for any problem.
- There is no single best method applicable to all learning situations. (correct)
- Learning methods are completely interchangeable for all problems.
- Some methods will always outperform others regardless of context.
What is the main bias found in Version Spaces according to Mitchell?
What is the main bias found in Version Spaces according to Mitchell?
- Assuming that only conjunctive concepts are valid. (correct)
- Assuming that unseen examples will behave the same as seen examples.
- Assuming linear relationships in the data.
- Assuming that the data is completely random.
What conclusion can be drawn about hypotheses in Version Spaces when allowing any concept?
What conclusion can be drawn about hypotheses in Version Spaces when allowing any concept?
- All hypotheses will predict the same target value.
- Half of the hypotheses will predict positive outcomes for unseen instances. (correct)
- Hypotheses become irrelevant when there is no bias.
- Only one hypothesis can exist for each instance in VS.
How does dropping bias affect generalization in learning methods?
How does dropping bias affect generalization in learning methods?
Which of the following is a type of classifier mentioned in the content?
Which of the following is a type of classifier mentioned in the content?
What is the primary goal of sequential covering in learning rules?
What is the primary goal of sequential covering in learning rules?
When learning a rule using a greedy search, which approach begins with the least specific rule?
When learning a rule using a greedy search, which approach begins with the least specific rule?
In the bottom-up approach, what is the main process for improving rules?
In the bottom-up approach, what is the main process for improving rules?
What is indicated by a rule covering an instance?
What is indicated by a rule covering an instance?
What does it mean when a rule has 'reasonable coverage'?
What does it mean when a rule has 'reasonable coverage'?
Which of the following is NOT a condition listed for learning a rule?
Which of the following is NOT a condition listed for learning a rule?
What type of learning does the phrase 'separate-and-conquer' refer to?
What type of learning does the phrase 'separate-and-conquer' refer to?
What assumption do decision trees make about the effects of variables on the outcome after a split?
What assumption do decision trees make about the effects of variables on the outcome after a split?
Which statement best explains the difference in assumptions between decision trees and linear regression?
Which statement best explains the difference in assumptions between decision trees and linear regression?
In the context of professor salaries, how does the application of linear regression fail?
In the context of professor salaries, how does the application of linear regression fail?
What is meant by 'inductive bias' in the context of learning algorithms?
What is meant by 'inductive bias' in the context of learning algorithms?
Which factor can influence whether trees or linear regression performs better for a given problem?
Which factor can influence whether trees or linear regression performs better for a given problem?
What is a potential consequence of consecutive splits in decision trees?
What is a potential consequence of consecutive splits in decision trees?
What does the term 'cumulative effects' imply in the context of learning models?
What does the term 'cumulative effects' imply in the context of learning models?
Why might understanding a problem be challenging when deciding between learning algorithms?
Why might understanding a problem be challenging when deciding between learning algorithms?
What is the condition under which a cocktail's shape being a trapezoid results in sickness?
What is the condition under which a cocktail's shape being a trapezoid results in sickness?
What is the likelihood of sickness associated with the color yellow in the cocktails dataset?
What is the likelihood of sickness associated with the color yellow in the cocktails dataset?
Which content level has the highest association with sickness based on the given dataset?
Which content level has the highest association with sickness based on the given dataset?
What is the result of combining the conditions of color orange and shape cylinder?
What is the result of combining the conditions of color orange and shape cylinder?
Which of the following conditions results in guaranteed sickness according to the dataset?
Which of the following conditions results in guaranteed sickness according to the dataset?
Based on the conditions, how many cases resulted in sickness for the combination of shape coupe and content 10cl?
Based on the conditions, how many cases resulted in sickness for the combination of shape coupe and content 10cl?
If the shape is a cylinder and color is white, what is the sickness likelihood?
If the shape is a cylinder and color is white, what is the sickness likelihood?
What can be inferred about the shape content of 25cl based on the dataset?
What can be inferred about the shape content of 25cl based on the dataset?
What is the key benefit of having higher coverage in a rule learner?
What is the key benefit of having higher coverage in a rule learner?
How does the m-estimate function adjust based on the parameters p, n, m, and q?
How does the m-estimate function adjust based on the parameters p, n, m, and q?
What is a potential disadvantage of the example-driven top-down rule induction?
What is a potential disadvantage of the example-driven top-down rule induction?
In the context of rule learners, what does the term 'coverage' refer to?
In the context of rule learners, what does the term 'coverage' refer to?
Which rule can be inferred as likely leading to a higher accuracy based on coverage and prior performance?
Which rule can be inferred as likely leading to a higher accuracy based on coverage and prior performance?
What underlying principle is utilized in improving rule accuracy with the m-estimate?
What underlying principle is utilized in improving rule accuracy with the m-estimate?
What effect does the parameter m have in the m-estimate formula?
What effect does the parameter m have in the m-estimate formula?
What is the initial step in the example-driven top-down rule induction process?
What is the initial step in the example-driven top-down rule induction process?
What will happen if the shape is a trapezoid and the color is orange?
What will happen if the shape is a trapezoid and the color is orange?
Which combination will definitely result in the object being sick?
Which combination will definitely result in the object being sick?
Which rule can be optimized by re-learning in the context of other rules?
Which rule can be optimized by re-learning in the context of other rules?
In JRip's implementation, what does the rule 'tear-prod-rate = normal' conclude?
In JRip's implementation, what does the rule 'tear-prod-rate = normal' conclude?
What is the main difference between classification rules and association rules?
What is the main difference between classification rules and association rules?
Which of the following conditions does NOT lead to an object being sick?
Which of the following conditions does NOT lead to an object being sick?
What is the purpose of pruning in the rule learning process?
What is the purpose of pruning in the rule learning process?
What is indicated by an association rule that has 'client = yes' for cheese and bread?
What is indicated by an association rule that has 'client = yes' for cheese and bread?
Flashcards
Linear Regression
Linear Regression
A statistical method used to establish a linear relationship between a dependent variable (the outcome) and one or more independent variables (predictors). The goal is to find the line that best fits the data points.
Inductive bias
Inductive bias
A type of bias inherent in a learning algorithm, reflecting assumptions made about data or the underlying relationships. It influences the algorithm's generalization capabilities.
Assumption of Tree Learners
Assumption of Tree Learners
In decision trees, after a feature is used to split the data, each branch is built independently. The algorithm doesn't assume the influence of other features remains constant across the split.
Decision Trees
Decision Trees
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Linear Regression
Linear Regression
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Bias in ML
Bias in ML
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Generalization
Generalization
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Bias and Algorithm Choice
Bias and Algorithm Choice
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No Free Lunch Theorem
No Free Lunch Theorem
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Bias in Machine Learning
Bias in Machine Learning
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Conjunctive Concept
Conjunctive Concept
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Classification Problem
Classification Problem
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Rule-Based Learning
Rule-Based Learning
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Least Squares
Least Squares
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Exploratory Data Analysis (EDA)
Exploratory Data Analysis (EDA)
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Feature Selection
Feature Selection
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Rule Coverage
Rule Coverage
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Sequential Covering
Sequential Covering
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Rule Accuracy
Rule Accuracy
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General vs. Specific Rule
General vs. Specific Rule
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Greedy Search in Generality Lattice
Greedy Search in Generality Lattice
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Top-Down Rule Learning
Top-Down Rule Learning
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Bottom-Up Rule Learning
Bottom-Up Rule Learning
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Conditions for a Rule
Conditions for a Rule
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M-Estimate of a Rule
M-Estimate of a Rule
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Example-Driven Top-Down Rule Induction
Example-Driven Top-Down Rule Induction
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Low Coverage Penalty
Low Coverage Penalty
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Top-Down Rule Induction
Top-Down Rule Induction
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Rule Specificity
Rule Specificity
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AQ algorithm
AQ algorithm
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RIPPER
RIPPER
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JRip
JRip
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Association Rules
Association Rules
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Classification Rule
Classification Rule
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Rule Pruning
Rule Pruning
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Ordered Rule Set
Ordered Rule Set
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Rule Optimization
Rule Optimization
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Study Notes
Lecture 3: Decision Trees vs. Linear Regression
- Lecture 3 covered decision trees, linear regression, inductive bias, and rule learners.
- Linear regression models assume a linear relationship between variables.
- The linear model is represented as Y = a + b₁X₁ + b₂X₂ + ... + bₖXₖ, where Y is the dependent variable and X₁, X₂, ..., Xₖ are independent variables.
- The model is typically fitted to minimize the sum of squared vertical deviations from the line; this approach is known as the "least squares" method.
- Linear regression can be used for predicting Y given Xᵢ, understanding how well Y can be predicted from Xᵢ, identifying the effect each Xᵢ has on Y, and visualizing the connection between Xi, and Y.
- Coefficients (bᵢ) demonstrate how much Y changes with a one-unit increment in Xᵢ, while all other Xⱼ variables remain constant.
- The correlation coefficient (r) indicates the strength and direction of the linear relationship between Y and X. When one predictive variable is used, a correlation coefficient's value ranges from -1 to 1.
- The coefficient of determination (R²) measures the proportion of variance in Y explained by the independent variables. Its value ranges from 0 (no contribution from independent variables) to 1 (complete contribution from independent variables).
- Interpreting coefficients requires careful consideration of factors like scale and potential multicollinearity (correlations among independent variables).
- For non-numerical input variables (nominal), create k-1 dummy variables.
Important Assumptions
- Linear models implicitly assume that the effect of each variable on the target is constant, independent of other variables.
- Effects of different variables are additive.
- In statistics, this is referred to as "no interaction," meaning the effects of variables do not interact.
Complex Terms
- Introduce terms representing functions of other variables (e.g., X₁₂ , sin(X₂), X₁ X₂).
- Interaction terms (e.g., b₁₂ X₁ X₂) show how the effect of one variable (X₂) depends on a second variable (X₁).
Nominal Variables
- If input variables are symbolic (nominal), create k-1 dummy variables to represent k values of Xᵢ.
Trees vs Linear Regression & Inductive Bias
- Decision trees differ greatly from linear regression models. Coefficients' effect remains constant in linear models whereas they change in decision trees.
- Decision trees don't assume a constant effect of a variable on the target across all data points.
Assumptions of Tree Learners
- Branches developed independently.
- Variables can have different effects (e.g., positive in one branch negative in another).
- No assumption of constant effects.
- Decision trees sharply contrast the consistent assumptions that linear models possess.
Additional Note
- The effectiveness of decision trees and linear regression depends largely on the problem context.
- Learners whose biases fit well within their related problem sets exhibit superior performance.
Removing All Bias?
- Bias-free learning is theoretically impossible.
- No single optimal method exists for every problem.
- Models' bias consists of implicit assumptions made regarding the problem.
Mitchell's Proof
- Any possible concept (e.g., hypothesis) can be represented in the hypothesis space. This means any concept/hypothesis can be predicted in various ways.
Other Methods
- Other learning methods exist beyond decision trees and linear regression.
- These include Naive Bayes, probabilistic graphical models, and discriminant analysis.
Classifiers in 2-D
- Examples (visual depictions) of classifiers operating on 2D data are given.
Choices to Make
- Formulate the problem as a prediction task (e.g., regression, classification, probability prediction).
- Select a learning approach considering efficiency, bias, and the interpretability of the returned model.
Learning If-Then Rules
- Rule sets are collections of "if-then" rules.
- Rule sets can be ordered (rule i applies only if rules 1-i-1 don't apply) or unordered.
- Ordered rule sets exhibit "if-then-else if" behavior.
Rule Sets
- Rule sets are categorized into ordered and unordered.
- Ordered rule sets employ the "if-then-else if" statement.
- Rules of the type "if..., then..." make up a rule set.
Rules with Exceptions: Rule Sets vs Decision Lists
- Decision lists offer compactness compared to rule sets; however, interpreting a single rule in a decision list requires knowledge about other rules.
- Each rule in a rule set is valid in isolation.
Another Illustration
- Examples using rectangles provide visual illustration to represent the concept of a gray area.
Learning Rule Sets
- Converting decision trees into rule sets.
- Rule sets often contain overlapping conditions.
Sequential Covering
- The "separate-and-conquer" algorithm is used.
- A rule covers an instance if the instance meets criteria set by the rule.
- "Sequential Covering" follows "separate-and-conquer".
Learning One Rule
- Can be implemented as a "greedy search" within a generality lattice.
- Can be top-down (start with general, add conditions) or bottom-up (start with specific, remove conditions).
- Selecting conditions relies on heuristics.
Illustration on "cocktails" Dataset
- Data table with various characteristics (shape, color, content, sick) concerning different cocktails.
- Used for illustrating the "sequential covering" procedure.
RIPPER
- Popular rule-learning algorithm.
- Works using "separate-and-conquer" approach.
- Modified for pruning and ordered rule learning.
Rule Learning in Weka
- Weka includes an implementation of Ripper called JRip.
- Example of applying the method to the "contact lenses" and Soybean datasets.
Link: Association Rules
- Association rules are descriptive rules relating to patterns in a dataset. Algorithms focus on determining rule sets satisfying conditions rather than subsets.
- Example of a customer's purchase habits illustrating association rule concept.
Heuristics for Rules Learners
- Rule accuracy = positive cases/(positive + negative).
- Rule-based algorithms prioritize rules that are more precise. Using this accuracy measurement, we select rules with superior performance, and this approach is a crucial step in rule-learning algorithms.
Heuristics for Rule Learners (cont.)
- m-estimates offer a conservative approach to assessing accuracy by considering prior estimates of accuracy.
Example-Driven Top-Down Rule Induction
- Modification of standard top-down approaches.
- Data instances are selected for establishing an hypothesis space.
- Hypothesis spaces are significantly reduced.
- Approach is more efficient but less robust to noise.
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