📖 Diffy Books · free · read or listen
How Not to Be Fooled
Chapter 3, The Average That Lied, is the same giant-footprint trick you solve in a case.
Read the chapter →Chapter 3: The Average That Lied · about 6 min
Statistics & evidenceAges 9–14
Data Detective: spot when numbers fool you
Start here: The jumping contest · Which team really jumps better? Make it a fair test. · About 3 minutes
Play The jumping contest →No account needed · Nothing to download.
Join Pip the owl to investigate six playful data mysteries: compare jumping teams, sort giant footprints, invite a fair sample and repair misleading posters. Each mission has three visual challenges; an optional Number Lab keeps the deeper numerical exercises. Play all activities without login; sign in to save progress and view family reports. Diffy measures product use to improve the service.
No ads, ever
Product use measured
Free to play
Plays in any browser
What kids learn
- Catch a bigger number hiding a smaller success rate
- Line up footprints and see one giant pull the average
- Build a helper team that matches the whole village
- Un-stretch a misleading chart
- Give a surprising seed a fair test
- Plan picnic snacks from a small survey
- Older detectives (12+): Number Lab with percentages and percentage points
How it works
Manipulate the evidence before making a decision: equalize team sizes, order footprints, assemble a sample or change a chart baseline. Three generated challenges build from exploration to a fresh application, with specific feedback and optional clues. Number Lab retains detailed rate, summary, sampling and experiment exercises. Guest practice is temporary; sign in to save progress. This is introductory learning, not validated mastery or academic credit.
Ages 9–14 (younger kids with a grown-up). Kids can play without signing in; guest stars stay until you reload or close the page. A grown-up signs in once and adds a player for each kid, so Data Detective's stars and progress save to your account and follow you to any device.
Read the comic that goes with it
Also try
- Algebra WorkshopAges 9–14
Help Bolt balance mystery packs, fix machines and build number bots.
Play Algebra Workshop → - Enterprise SimulatorAges 9–14
Open Fern’s lemonade stall, serve customers and grow your money sense.
Play Enterprise Simulator →
Ready to play Data Detective?
It's free and has no ads. Diffy measures product use to improve the service. Ages 9–14 (younger kids with a grown-up).