Statistics & data mining

Learn statistics by doing it.

17 courses take you from “what is a mean” to clustering, decision trees and model evaluation — all inside Excel, the tool you already have. Every lesson comes with a lab you work through in the browser: you type the formula, you see the number, the server tells you whether it is right.

The first course is free in full — lessons, labs, final exam and the certificate. No card, no trial clock.

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A lab in every lesson

A real spreadsheet in the page, with real data. Write =STDEV.S(B2:B21), get the number, get told if it is the right one. 126 labs so far.

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University-level, not tips

Assumptions, when a test breaks, what a p-value really says. The maths is explained, then done — with the exact Excel function that does it.

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A certificate per course

Pass the final exam and get a certificate with a public verification link and a PDF — one for every course you finish.

The honest part

Excel is not R. We say where the line is.

Most of what a working analyst does — describing data, testing a difference, fitting and checking a regression, forecasting, clustering, evaluating a classifier — Excel does perfectly well, and these courses show exactly how. Where Excel needs the Analysis ToolPak, Power Query or Solver, the lesson names it. Where Excel genuinely runs out (random forests, mixed models, millions of rows), the lesson says so instead of faking it, and tells you what the next tool would be.

Curriculum

17 courses, in order

17 courses · 136 lessons · one certificate each

🧱 Data Foundations
Get your data into the shape every statistical method silently assumes.
Free, in full
📊 Descriptive Statistics
Summarise a column so that the number you report is the number you mean.
8 lessons · Beginner
🎲 Probability and Distributions
Turn a column of outcomes into probabilities, and know which curve you are entitled to use.
8 lessons · Beginner
🎯 Sampling and the Central Limit Theorem
Why forty measurements can speak for forty thousand — and the conditions under which they cannot.
8 lessons · Beginner
📏 Confidence Intervals
What an interval estimate actually claims, what it never claims, and how to build one in Excel.
8 lessons · Intermediate
⚖️ Hypothesis Testing
What a p-value measures, what it cannot measure, and how to run a test you can defend.
8 lessons · Intermediate
⚖️ t-Tests
Decide whether a difference in means is bigger than the noise — and know which of the three tests you are entitled to use.
8 lessons · Intermediate
🧮 ANOVA
Compare three or more groups in one test, and find out where the difference lives without inventing significance.
8 lessons · Intermediate
🔲 Chi-Square Tests
Test counts instead of means: does this distribution match what you expected, and are these two categories related?
8 lessons · Intermediate
🪜 Nonparametric Tests
Test differences with ranks when the mean is the wrong summary — and build every statistic by hand, because Excel has none of them.
8 lessons · Intermediate
🔗 Correlation
Measure how two columns move together, test whether it is real, and learn everything r refuses to tell you.
8 lessons · Intermediate
📈 Simple Regression
Fit one line to two columns, say precisely what its slope means, and know how far to trust the number it predicts.
8 lessons · Intermediate
📐 Multiple Regression
Estimate the effect of one variable while the others are held still — and know exactly what that sentence buys you.
8 lessons · Advanced
🩺 Regression Diagnostics
Interrogate a fitted model until it either earns your trust or admits what it is hiding.
8 lessons · Advanced
🎯 Logistic Regression
Model a yes/no outcome properly: odds, log-odds, maximum likelihood and Solver.
8 lessons · Advanced
📈 Time Series Basics
Trend, season and noise — and why the order of the rows changes every rule you know.
8 lessons · Intermediate
🔮 Forecasting
Holt-Winters, Excel's ETS tools, error measures — and the naive forecast you have to beat.
8 lessons · Intermediate

Start with the free course.

If it teaches you something you can use tomorrow, the rest are waiting.

Open Data Foundations