K-Means Clustering Method & Python Codes
K-Means Clustering is a popular unsupervised machine learning algorithm used for clustering data into groups. It is widely used in…
Category: machine learning in a random forest
Logistic regression with L1 or L2 penalty with codes in Python and R
Logistic regression with L1 or L2 penalty adds regularization to prevent overfitting and improve model generalization. L1 penalty (Lasso) encourages sparsity in the model, making it suitable for datasets with many irrelevant features. L2 penalty (Ridge) retains all features with reduced importance. Python and R codes demonstrate implementation and evaluation of these regression techniques.
What’s classification
Classification organizes items based on criteria. In data, it involves sorting into categories. It’s manual or automated with algorithms. Used in science, business, and technology to analyze and predict based on data. Crucial in document categorization, image recognition, sentiment analysis, and spam filtering for efficient data organization and analysis.
Adjusted R squared
The coefficient of determination, or R-squared, measures how well an independent variable explains the variability of a dependent variable in a regression model. Its limitation lies in the fact that it does not decrease when a new feature is added, whether useful or not. Adjusted R-squared is an improvement, considering the number of predictors in a model, making it more reliable for assessing explanatory power.
Feature selection & Model Selection
Feature selection involves identifying and including essential variables in the model, possibly leading to improved performance and interpretability. Adjusted R-squared is a common metric for regression analysis, addressing overfitting by penalizing unnecessary variables and offering an accurate model representation.
Sum of Squares & coefficients of determination with Python & R codes
The coefficient of determination (R-squared) measures how well a model explains the variance of the response variable. In this example, Python and R are used to calculate R-squared for linear regression. Higher R-squared value and the plot indicate a good fit, demonstrating the effectiveness of the model.
Non-constant variance in linear regression: a duck’s mood swing problem
This content provides an example of simulating and detecting heteroscedasticity in data using Python. We simulate the data, fit the model, and analyze how to detect heteroscedasticity, and how to address this using a log transformation.
Multiple linear regression
Multiple linear regression is a powerful tool for modeling relationships between multiple independent variables and a single dependent variable. Let’s take a look at some examples with codes in Python and R to demonstrate its practical application
Review: Maximum Likelihood Estimation
Maximum Likelihood Estimation (MLE) is a statistical method that estimates parameters by maximizing the likelihood function. For example, in a Poisson distribution, the MLE for the rate parameter ? is the sample mean. And here is the detailed derivation
Comparing forward, backward, stepwise feature selection
Forward selection adds features one by one, optimizing model performance but potentially missing the best subset. Backward selection starts with all features and removes the least significant, refining the model but being more computationally intensive. Stepwise selection combines both methods, adding or removing features for a balanced approach but can be complex.