Stats 1: Introduction to Statistics
Eighteen lessons take you from your first bar chart to your first regression line, each pairing a plain-language explanation with an interactive you can drag until the idea clicks. The course follows the syllabus of Statistics 1 (UCG1RM11) at University College Groningen week by week, so a student on that course finds the whole block here, in teaching order.
No stats background is assumed, and no formula appears before the picture it describes. The spine of the course is one story: how a handful of honest descriptions of data (means, spreads, shapes) turn into tools for reasoning about people you never measured. Sampling distributions and the central limit theorem carry that story, and hypothesis testing and confidence intervals finish it. The last stretch turns outward, to counts, to correlation, and to the straight line through a scatterplot.
Work through it in order if you're new; each lesson leans on the ones before it. If you studied statistics years ago and just want the rust off, jump straight to section 1.9 and let the sampling machinery surprise you again. When you're done, Stats 2 continues with ANOVA and the inferential half of regression.