Free public beta until December 4, 2026: every course is open, no card needed. After that, the first chapter of each course stays free and full access is a one-time $39 ($19 for up to 100 founding members chosen for helpful feedback). Your progress is kept. How the beta works

statistics

Adding a second predictor

taught

Taught in

Adding a second predictor
Statistics

Requires

influential-points-on-the-regression-line required

Required by

Interpreting a partial-slope coefficient required

Local knowledge map

Local knowledge map

Click to expand

Solid arrows are required prerequisites; dashed are recommended or helpful. Lower rows are more foundational. Click any box to jump to that concept.