FlowingData
Visualization-focused tutorials and guides on analyzing and presenting data effectively.
LearnPython.org
Interactive, browser-based Python tutorials ranging from basic syntax to advanced modules.
Math StackExchange
A global community where advanced math students and professionals ask and answer detailed mathematics questions, from abstract algebra to applied math.
AI Engineering
Andrew Ng
A practical framework for building real-world AI applications from foundational principles
OpenStax Mathematics
Peer-reviewed, openly licensed textbooks covering college algebra, calculus, and statistics; downloadable for free in PDF or web format.
Coursera - R Programming (Audit Free)
Johns Hopkins University?s R Programming course (part of the Data Science Specialization), free in audit mode with videos and quizzes.
Microsoft Learn ? Power BI
Official Microsoft Learn platform with guided, hands-on modules for Power BI, covering everything from basics to advanced analytics.
MiT Open CourseWare
MIT OpenCourseWare offers free access to thousands of MIT course materials?lectures, assignments, and exams?covering subjects from engineering and computer science to economics and the humanities. It's open learning at its best, with no registration required.
Princeton Review GRE Practice
Free practice test access, strategy sessions, and sample GRE questions.
Dataquest Free Data Analysis Courses
Browser-based lessons in Python, SQL, and data visualization; first modules free.
OpenIntro Statistics
Free, open-source statistics textbook with R labs and applied data analysis examples.
Connections Wargaming Conference
Annual international conference linking defense, industry, and academia to advance professional wargaming practice.
Microsoft Learn - Data Analysis
Free learning paths covering data analysis basics and Power BI dashboards directly from Microsoft.
Harvard Business School Online - Data Science Ready (Free Modules)
Intro modules teaching how analytics applies to business decisions, tailored for managers and analysts.
DataCamp Free Courses
Free beginner-friendly courses in data analysis with Python, R, and SQL; includes guided projects.
OpenLearn - Learn to Code for Data Analysis
Free Open University course introducing Python programming in the context of data analysis.
Magoosh GRE Blog
Hundreds of free articles, study guides, vocabulary lists, and strategies for GRE verbal, quant, and writing.
LeetCode SQL Problems
Collection of SQL coding challenges to practice writing queries, often used in interview preparation.