Basic Concepts in ML

Statistics for ML

  • Statistical Reasoning
  • Curse of Dimensionality
  • Frequentist vs. Bayesian Probability
  • Probability Distributions
  • Central Limit Theorem vs. Law of Large Numbers
  • Assessing skewed data
  • Categorical vs. continuous variables
  • Statistical Tests
  • Hypothesis Test
  • p-value; significance level; statistical power; confidence interval
  • t-test
  • ANOVA
  • Chi-square

ML Models

  • Parametric/Non-parametric
  • Supervised/Unsupervised
  • Supervised
  • Loss Function
  • Regularization (what is it and why is it useful?)
  • Underfitting/Overfitting
  • Bias vs. Variance Tradeoff (f-hat and flexibility of model)
  • Datasets – Train, test
  • K-Fold Cross Validation
  • Variable transformations
  • Exploratory Data Analysis – checks and interpretation
  • Histograms, scatterplots, correlation matrix, numerical summary
  • Bagging / Boosting / Stacking

Simple / Multiple Regression

  • Collinearity
  • Model assumptions – ex. residuals
  • Interpret Model Output / Model Performance Measures
  • R^2, adjusted R^2
  • p-value for each term
  • Coefficients
  • p-value for model
  • Residuals
  • Outliers
  • F-statistic
  • Accuracy (MSE, RMSE)

Classification

  • Imbalanced classes
  • Undersampling/Oversampling
  • Decision trees
  • Support vs. Confidence
  • Model Performance Measures
  • Contingency table
  • Confusion Matrix - errors
  • ROC Curve
  • Precision vs. Recall
  • TPR/FPR
  • Lift
  • AUC
  • Accuracy calculation: = (TP+TN)/(TP+TN+FP+FN)
  • Models - understand how they work and how output of each looks visually
    • K-Nearest Neighbor
    • Logistic Regression
    • Random Forest
    • Support Vector Machine/Classifier – kernel
    • Naïve Bayes
    • Neural Network

Model Features/Selection

  • Wrapper vs. filter method
  • Feature Selection
  • Feature Creation
  • Stepwise Regression (what is difference between forward and backward?)
  • Dimension Reduction
  • PCA

Added

  • One-hot-encoding
  • Mean squared error: MSE
  • Cross-entropy function)
  • Loss Function
  • Cost Function
  • Regularization
  • L1 Regularization (Lasso)
  • L2 Regularization (Ridge)
  • Normalization
  • Scaling
  • AutoEncoder
  • Gradient Descent

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