W3Schools Python
Step-by-step interactive lessons for Python basics, data structures, and functions, with hands-on coding snippets.
Project Euler
Hundreds of challenging computational math problems that build problem-solving and programming skills.
UK Fight Club (Professional Wargaming Network)
Community that promotes professional military wargaming and simulation activities across UK defense.
Ready4GRE Vocabulary App
Free app with flashcards, quizzes, and personalized study plans for GRE vocabulary practice.
The Carpentries - Data Carpentry
Community-driven lessons for researchers covering data organization, cleaning, visualization, and analysis in R, Python, and SQL.
ModernDive: Statistical Inference via Data Science
Free online textbook teaching statistical inference and regression using R and tidyverse methods.
UC Berkeley Data 8 (Foundations of Data Science)
Introductory data science/analytics course using Python; includes lectures, labs, and exercises for free online.
CrunchPrep GRE Blog
Guides and strategies for GRE preparation including word lists, essay templates, and quantitative shortcuts.
SQL Shack ? Power BI
Collection of practical Power BI tutorials and tips, especially useful for SQL Server professionals integrating BI dashboards.
Google Data Analytics Certificate (Audit Free)
Comprehensive beginner-to-intermediate program covering spreadsheets, SQL, R, visualization, and analytics workflows; free in audit mode.
Saylor Academy - Mathematics
Free, full-length math courses (Linear Algebra, Abstract Algebra, Real Analysis, etc.) with exams and certificates.
OpenIntro Statistics
Free, open-source statistics textbook with R labs and applied data analysis examples.
Springboard Data Analytics Curriculum (Free Prep)
Introductory lessons and exercises to build foundation skills in Excel, SQL, and data storytelling.
RADACAD Power BI Blog
Practical tutorials and tips on Power BI modeling, DAX, Power Query, and real-world scenarios written by MVPs.
LeetCode SQL Problems
Collection of SQL coding challenges to practice writing queries, often used in interview preparation.
Khan Academy - Advanced Math
Free structured lessons with videos and practice exercises covering algebra, calculus, statistics, linear algebra, and differential equations.
StatQuest with Josh Starmer (YouTube)
Clear and approachable explanations of statistics and data analysis, breaking down complex concepts into simple steps.
Power BI Guided Learning (Microsoft)
Step-by-step tutorials directly from Microsoft, teaching data connection, modeling, visualization, and publishing dashboards.
DataCamp (Free R Tutorials)
While DataCamp is subscription-based, it offers free introductory R courses covering basics, data manipulation, and visualization.
Microsoft Learn - Data Analysis
Free learning paths covering data analysis basics and Power BI dashboards directly from Microsoft.