Terms and definitions from all courses

Variable: A named container which stores values in a reserved location in the computer’s memory
Variable selection: The process of determining which variables or features to include in a given model
Variance inflation factors (VIF): Quantifies how correlated each independent variable is with all of the other independent variables
Variance: Refers to model flexibility and complexity, so the model learns from existing data; the average of the squared difference of each data point from the mean
Vectorization: A process that enables operations to be performed on multiple components of a data object at the same time
Voluntary response sample: A method of non-probability sampling that consists of members of a population who volunteer to participate in a study

W

Ward: Merges two clusters whose merging will result in the lowest inertia Weak learner: A model that performs slightly better than randomly guessing While loop: A loop that instructs the computer to continuously execute the code based on the value of a condition

X

XGBoost (extreme gradient boosting): An optimized GBM package

Z

Zero Frequency problem: Occurs when the dataset has no occurrences of a class label and some value of a predictor variable together


Z-score: A measure of how many standard deviations below or above the population mean a data point is