Regression and Classification Algorithms
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Questions and Answers

Residuals are calculated by adding the predicted value to the actual value.

False

The Sum of Squared Errors (SSE) is the sum of all squared residuals.

True

Gradient descent is a method used to maximize the loss function in linear regression.

False

R-squared values closer to 0 indicate a better fit of the regression model.

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

Adjusted R-squared is more useful for comparing models with the same number of predictors.

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

Lower Root Mean Square Error (RMSE) values indicate smaller prediction errors.

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

The iterative optimization process involves updating coefficients based on random selection rather than gradients.

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

Mean Squared Error (MSE) is a measurement of the average of squared residuals.

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

The assumption of normality implies that the residuals should be uniformly distributed.

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

Homoscedasticity means that the variance of the residuals increases with the values of the independent variables.

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

The key concepts in linear regression include assumptions such as heteroscedasticity.

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

The independence assumption states that one observation should not affect another observation.

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

The absence of multicollinearity means that independent variables should be highly correlated.

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

The Lasso regression algorithm is a type of linear regression that does not apply any regularization.

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

The linearity assumption requires a linear relationship between dependent and independent variables.

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

R-squared is a metric commonly used in regression analysis.

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

If any assumptions of linear regression are violated, the results will always be reliable.

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

Residuals are the differences between observed values and predicted values in regression.

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

Heteroscedasticity refers to constant variance of the residuals across levels of independent variables.

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

The random forest regressor uses a single decision tree to make predictions.

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

The requirement of homoscedasticity is crucial for the validity of a linear regression model.

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

Gradient Descent is a method used to optimize models by minimizing the loss function.

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

The ElasticNet regression combines L1 and L2 regularization in its approach.

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

Logistic regression is primarily used for regression analysis rather than classification tasks.

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

In logistic regression, the Logistic function always provides a number greater than 1.

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

Decision trees can only be used for binary classification.

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

Gini impurity measures the disorder or impurity in a dataset.

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

A Gini impurity of 0 indicates maximum impurity in a dataset.

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

The goal when developing logistic regression models is to choose coefficients that predict high probabilities when y = 0.

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

The decision tree algorithm divides the feature space into multiple partitions at once.

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

The highest Gini impurity occurs when elements are evenly distributed across classes.

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

The split that results in the highest Gini impurity is chosen as the best split at each node of the tree.

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

A higher threshold value will decrease the number of false negatives.

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

Decreasing the threshold will always reduce the number of true positives.

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

The threshold value can impact the trade-off between false positives and false negatives.

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

A threshold of 0.60 will result in more false positives compared to a threshold of 0.80.

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

False negatives will increase if the threshold is decreased.

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

True negatives will always decrease when the threshold is increased.

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

The predicted probability of a machine learning model is always between 0 and 1.

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

Increasing the threshold decreases both true positives and false positives.

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

Study Notes

Regression

  • Different algorithms for regression: Ordinary Least Squares, Lasso, Ridge, ElasticNet, Decision Tree, Random Forest, Linear Support Vector Regression
  • Assumptions: linearity, independence, homoscedasticity, normality, absence of multicollinearity

Linear Regression

  • Key concepts: regression coefficients, residuals (errors), sum of squared errors (SSE)
  • Gradient descent: iterative optimization to minimize residuals by updating coefficients based on gradients of the loss function
  • Commonly used metrics: R-squared, adjusted R-squared, RMSE

Logistic Regression

  • A classification algorithm that predicts the probability of an outcome
  • Logistic function maps values between 0 and 1, representing the probability

Decision Trees

  • Recursive partitioning algorithm used for classification and regression
  • Uses Gini impurity (measure of disorder) to make decisions about splitting data at each node

Gini Impurity

  • Ranges from 0 (pure) to 1 (most impure)
  • 0 indicates all elements belong to the same class
  • 1 indicates elements are evenly distributed across classes

Receiver Operating Characteristic (ROC) Curve

  • Plots the true positive rate against the false positive rate
  • Used to evaluate the performance of classification models
  • Area under the curve (AUC) indicates the model's ability to distinguish between classes
  • Threshold value controls the trade-off between false positives and false negatives
  • Increasing the threshold: decreases true positives and false positives, increases true negatives and false negatives
  • Decreasing the threshold: increases true positives and false positives, decreases true negatives and false negatives

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Description

This quiz covers various regression techniques including Ordinary Least Squares, Lasso, and Logistic Regression. It also delves into key concepts like regression coefficients, gradient descent, and evaluation metrics such as R-squared. Test your understanding of decision trees and Gini impurity too.

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