StudyDSA logoStudyDSA

Command Palette

Search for a command to run...

Sign InSign Up
Sign Up

Data StructuresAlgorithmsBig-O NotationSystem DesignMachine LearningRoboticsAI ResearchGlossary

Definition
StudyDSA

Where complexity meets clarity.
By Armas Zarra.

Topics

  • Data Structures
  • Algorithms
  • Big-O Notation
  • Robotics
  • AI Research
  • Machine Learning

Practice

  • Blind 75
  • LeetCode 75
  • NeetCode 150

Legal

  • Privacy Policy
  • Terms of Service

© 2026 Armas Films LLC

IntroductionGlossary

Glossary

Every term StudyDSA teaches, starting with machine learning words like overfitting, bias, and variance. Each one links to the lesson section that explains it.

Machine Learning

  • Bayes error

    the lowest error rate any classifier can reach on a problem, because some examples genuinely look like the other class

    k-Nearest Neighbors
  • bias

    how far off the predictions still are after averaging over every batch: an offset built into the model's shape

    k-Nearest Neighbors
  • classification

    predicting a category, like spam or not spam, cat or dog

    k-Nearest Neighbors
  • dimensions

    the number of axes an example lives on, one per feature

    k-Nearest Neighbors
  • example

    one thing you have data on: one email, one house, one motor

    k-Nearest Neighbors
  • features

    the numbers used to describe an example, like an email's link count and its exclamation mark count

    k-Nearest Neighbors
  • label

    the answer attached to an example, like spam or not spam, or a house's sale price

    k-Nearest Neighbors
  • lazy learner

    a method that does all of its computing at prediction time instead of learning something up front

    k-Nearest Neighbors
  • min-max scaling

    rescaling a feature so its smallest value lands at 0 and its largest lands at 1

    k-Nearest Neighbors
  • overfitting

    fitting the training examples so tightly that the model also fits their mistakes and random quirks, which don't repeat on new data

    The classic sign is a training error near 0 while the test error climbs. The model stopped learning the pattern and started memorizing the exact pile it was handed, quirks included. Both curves below run through the same points, but only one of them will hold up on tomorrow's data:

    memorizes every point
    follows the pattern
    k-Nearest Neighbors
  • regression

    predicting a number, like a price or a lifetime in hours

    k-Nearest Neighbors
  • standardizing

    rescaling a feature so its average lands at 0 and the values are measured in standard deviations away from it

    k-Nearest Neighbors
  • supervised learning

    learning from examples that come with their answers, supplied ahead of time by a person

    k-Nearest Neighbors
  • test error

    the error rate measured on examples the model has never seen before

    k-Nearest Neighbors
  • test set

    labeled examples kept away from the model, so its mistakes on them predict its mistakes on new data

    k-Nearest Neighbors
  • training data

    the pile of examples that already carry labels, the only thing the algorithm gets to learn from

    k-Nearest Neighbors
  • training error

    the error rate measured on the examples the model has already seen

    k-Nearest Neighbors
  • underfitting

    a model too blunt to follow the real pattern, so it scores badly on the training examples and on new ones too

    k-Nearest Neighbors
  • variance

    how much a model's prediction for one point changes from one training batch to the next

    k-Nearest Neighbors