Supervised learning involves training an algorithm on labeled data and pairing input with correct output. Unsupervised learning uses unlabeled data to find patterns. For example, predicting pizza delivery tips involves features like time, pizza type, distance, and tip history, with the goal of predicting tip outcomes.
After collecting and preprocessing the dataset, it is essential to divide it into two distinct sets: training set and testing set. The training set is used to train the model while the testing set is used to evaluate its performance. This allows assessment of the model’s generalization to new data. Two code examples in Python and R demonstrate how to create synthetic data and split it into training and testing sets using popular libraries.
Model generalization in machine learning is a crucial concept that refers to the ability of a trained model to perform well on new, unseen data. When a model generalizes well, it demonstrates an understanding of… A comic guide to model generalization and overfitting
Simple linear regression is a statistical method used to model and analyze the relationship between two continuous variables. Specifically, it aims to predict the value of one variable (the dependent or response variable) based on… Simple Linear Regression Review: Sunlight & Selfie
Assessing assumptions like linearity, constant variance, error independence, and normal residuals is essential for linear regression. Residual plots visually assess the model’s goodness of fit, identifying patterns and influential data points. This post provides the Python & R codes for the residual plot
Simple linear regression is a statistical method to model the relationship between two continuous variables, aiming to predict the dependent variable based on the independent variable. The regression equation is Y = a + bX, where Y is the dependent variable, X is the independent variable, a is the intercept, and b is the slope. The method of least squares minimizes the sum of squared residuals to find the best-fitting line coefficients.
Model ensembling combines multiple models to improve overall performance by leveraging diverse data patterns. Bagging trains model instances on different data bootstraps, while Boosting corrects errors sequentially. Stacking combines models using a meta-model, and Voting uses majority/average predictions. Ensembles reduce variance without significantly increasing bias, but may complicate interpretation and computational cost.
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Consider the use of accuracy, precision, recall a funny classification problem in a medical scenario set in a forest involving forest animals. So, the data has: Total Forest Animals Tested: 1000Animals with Silly Squirrel Syndrome… Acc, precision, recall in detecting Rare “Silly Squirrel Syndrome” in Forest Animals
Handling categorical data involves several steps to convert it into a format that machine learning algorithms can process effectively. Here are common methods used to handle categorical data: 1. Label Encoding Label encoding converts categorical… Encoding categorical data in python
This example demonstrates the basic steps of stack generalization with two classifiers (KNN and Random Forest) and a Logistic Regression model as the meta-learner. The predictions of the base models on the training data are… example of stack generalization using K-Nearest Neighbors (KNN) and Random Forest + Python codes
Some popular types of kernels in SVM: 1. Linear Kernel 2. Polynomial Kernel 3. Radial Basis Function (RBF) Kernel (Gaussian Kernel) 4. Sigmoid Kernel Visualizing the decision boundaries To visualize the decision boundaries, we’ll use… Kernel tricks, SVM properties & kernel choice
Logistic regression is a statistical method used for analyzing datasets in which there are one or more independent variables that determine an outcome. The outcome is typically a binary variable, meaning it has two possible… Logistic Regression: method + Python & R codes
Akaike Information Criterion (AIC) Bayesian Information Criterion (BIC) Comparison and Use in Feature Selection By applying AIC and BIC in feature selection, we can make informed decisions about which features to include in their models,… AIC and BIC for Feature Selection
We should normalize or standardize data before applying KNN because the algorithm is distance-based, and unscaled features can distort distance calculations, leading to biased results. In this example, we’ll use the Iris dataset, which is… KNN classification: practical notices & implementation using Python & R
K-Nearest Neighbors (KNN) is a popular algorithm used for both classification and regression tasks. In KNN, the output is a class membership, which is assigned based on the majority of the k nearest data points.… K-Nearest Neighbors (KNN): an introduction
Linear Discriminant Analysis (LDA) is a classifier that creates a linear decision boundary by fitting class-conditional densities to the data and applying Bayes’ rule. The model assumes that each class follows a Gaussian distribution with… Linear Discriminant Analysis Implementation in Python & R
Stepwise feature selection is a systematic approach to identifying the most relevant features for a predictive model by combining both forward and backward selection techniques. The process begins with either an empty model. Then, we… Stepwise Feature Selection +example
Backward feature selection involves iteratively removing the least significant feature from a model based on adjusted R-squared. In this example, we are predicting nuts collected by squirrels, features like temperature and rainfall are chosen as significant predictors through this method. The process aims to finalize a model with the most influential features.
Forward feature selection starts with an empty model and adds features one by one. At each step, the feature that improves the model performance the most is added to the model. The process continues until… Forward feature selection: a step by step example
ElasticNet regression is a regularized regression method that linearly combines both L1 and L2 penalties of the Lasso and Ridge methods. This allows it to perform both feature selection (like Lasso) and maintain some of… ElasticNet Regression: Method & Codes
Motivation Now, recall that for LASSO Ridge Regression: Ridge regression: Ridge adds the penalty, which is the sum of the squares of the coefficients, to the loss function in linear regression. Ridge regression shrinks the… Ridge regression: method & R codes
The Lasso (Least Absolute Shrinkage and Selection Operator) is a regression technique that enhances prediction accuracy and interpretability by applying L1 regularization to shrink coefficients. Unlike traditional regression methods, Lasso forces some coefficients to become… Lasso Regression and LassoCV: methods & Python codes
An example of performing simple linear regression using train-test split where the process is as follows, 1. Generate a synthetic dataset: 2. Split the dataset: We use train_test_split to divide the data into training and… Simple linear regression using train-test split in Python & R
Expectation Maximization (EM) is an iterative algorithm used for finding maximum likelihood estimates of parameters in statistical models, particularly when the model involves latent variables (variables that are not directly observed). The algorithm is commonly… Expectation Maximization (EM) & implementation
Handling noisy data is a crucial step in data preprocessing and analysis. In general, here are some common approaches to manage noisy data: 1. Data Cleaning 2. Data Transformation 3. Statistical Techniques 4. Machine Learning… A comic guide to denoising noisy data
Recall that Missing Not At Random (MNAR) is a type of missing data mechanism where the probability of missingness is related to the unobserved data itself. Here are some more examples of MNAR: In each… A comical guide to Missing Not At Random (MNAR)
Missing at Random (MAR) is a statistical term indicating that the likelihood of data being missing is related to some of the observed data but not to the missing data itself. This means that the… What’s Missing at Random (MAR)?
Multiple regression analysis can be used to understand the relationship between the waiting time to log in to Windows (dependent variable) and several independent variables. Let’s assume we have the following independent variables: Suppose that… Multiple regression analysis: waiting time to log in to Windows
Graphical Lasso, also known as GLasso, is a statistical technique used for estimating the sparse inverse covariance matrix (precision matrix) of a multivariate Gaussian distribution. Here, Sparsity means that many elements of the matrix are… Estimating the sparse inverse covariance matrix (precision matrix) by Graphical Lasso (with Python implementation)
Generating missing values Generating missing values with a given percentage of missingness for a dataframe or numpy array: Generating missing values with a given missing rate for a time series list: Calculating MSE ignoring missing… Generating missing data and evaluating missing data analysis in Python
Principal Component Analysis (PCA) is a statistical technique used for dimensionality reduction, which simplifies the complexity in high-dimensional data while retaining important infomation. The basic idea of this method is to transform a large set… Introduction to Principal Component Analysis (PCA) and implementation in R and Python