Pettigrew LabTry a lesson

Five-minute lessons that take you from the stuff your phone records every morning to how chatbots like ChatGPT write back. Built for curious teens, parents and grandparents. No math needed.

On iPhone, iPad and Android now. The first part is free.

The people in it

Five people you’ll keep running into

Every lesson is a story about one of them: Maya’s channel, Sam’s first car, Priya’s questions, Dre’s game. By the end you’ll know them well enough to guess what Priya is about to ask.

  • Maya

    Runs a small gaming channel. Her 14th video is the mystery.

  • Sam

    The saver. Flips sneakers to save for his first car.

  • Priya

    The skeptic. Writes for the school paper and asks who got counted.

  • Dre

    The athlete. Plays JV basketball and has the stats to argue for more minutes.

  • Nana

    Maya’s grandmother. Across the table for every Dinner Table Challenge.

Module 1 · Your digital footprint

By lunch, what does your phone already know about you?

It’s a school day. Drag the clock through Maya’s morning. Everything that lights up just wrote something down about her, and your phone does the same about you.

Time of day

Maya

6:40 AM

6:40 AM12:30 PM

Nothing yet. Drag the clock.

  1. 6:45 AM

    Maya’s alarm goes off

    Her phone notes what time she woke up.

  2. 6:52 AM

    She unlocks her phone with her face

    Face unlock compares her face to the one it has on file.

  3. 7:05 AM

    She scrolls for a few minutes

    The app logs what she watched and how long she stayed on each one.

  4. 7:40 AM

    She heads out the door

    With location on, her phone keeps track of where she goes.

  5. 8:10 AM

    She joins the school Wi-Fi

    The network logs her phone and the minute it showed up.

  6. 12:15 PM

    She taps to pay for lunch

    Her bank records what she bought, where and for how much.

Maya didn’t type any of that in. It was written down about her, by machines, while she ate breakfast. That’s data. The rest of the course is about what happens to it next.

Try it · Module 15 · Linear regression

Sam has saved up for his first car and it’s down to Car A or Car B. Here are 15 used Civics for sale, those two included. Drag the two yellow handles so the line runs through the middle of the dots. That line is your guess at what a car should cost for its miles.

$10k$15k$20k$25k0k30k60k90k120kMiles on the carAsking priceAB

Example data, made up for this lesson.

Drag the yellow handles, or use the sliders under the chart. When it looks right, check it.

What is linear regression?

Linear regression finds the straight line that fits a set of points best, so you can predict one number from another. Here it predicts a used car’s price from its miles: the slope says every 10,000 miles knocks about $1,100 off, and a car sitting below the line costs less than the pattern says it should.

Two more from the course

Once you see these, you see them everywhere

Module 7 · Mean vs. median

Dre

A billionaire walks into the cafeteria. Did anyone at lunch get richer?

Dre pictures ten adults eating lunch in the school cafeteria. Tap the button and watch what one billionaire does to the average income in the room.

Average income (mean)
$56,400
The middle person (median)
$53,500

Module 10 · Correlation vs. causation

Priya

Does ice cream cause sunburns?

Priya finds a beach town that counts ice cream sales and sunburns every month, and they rise and fall together. So should the town stop selling ice cream?

0122436Ice cream salesSunburnsJan: 20 ice cream sales, 2 sunburnsFeb: 24 ice cream sales, 3 sunburnsMar: 35 ice cream sales, 6 sunburnsApr: 50 ice cream sales, 11 sunburnsMay: 70 ice cream sales, 18 sunburnsJun: 95 ice cream sales, 27 sunburnsJul: 110 ice cream sales, 33 sunburnsAug: 105 ice cream sales, 31 sunburnsSep: 75 ice cream sales, 19 sunburnsOct: 45 ice cream sales, 8 sunburnsNov: 28 ice cream sales, 4 sunburnsDec: 22 ice cream sales, 2 sunburns
Example data, made up for this lesson.

The whole course

24 modules, from the data on your phone to how chatbots work

Every module is four five-minute lessons, about 20 minutes, with something to play with in each one.

Teaching it? See how each module maps to Common Core and CSTA standards

Part I

Your Data

What data is, and where it goes after you make it.

  1. 01What does my phone write down about me?You’re a Data Source · Your digital footprint
  2. 02Is a photo data? Is a text message?What Counts as Data · Structured vs. unstructured data
  3. 03Where does it all go once it’s written down?Where Data Lives · What a database is

Part II

Getting It Ready

Spreadsheets, cleanup and asking a fair question.

  1. 04What can a spreadsheet do that I can’t do in my head?Spreadsheet Superpowers · Excel and Google Sheets basics
  2. 05What happens when the data has typos?Clean It or It Lies · Data cleaning
  3. 06Why does asking the wrong people give the wrong answer?Good Questions, Fair Data · Sampling bias

Part III

Making Sense of It

The statistics you run into every day, minus the homework.

  1. 07Why is “the average” sometimes a lie?Averages That Lie · Mean vs. median
  2. 08What does “95th percentile” actually mean?Spread, Shape and Percentiles · Standard deviation and percentiles
  3. 09Is a 5-star rating from 3 people worth anything?Chance, Samples and Star Ratings · Probability and sample size
  4. 10If two things move together, did one cause the other?Correlation Isn’t Causation · Correlation vs. causation

Part IV

Showing and Testing

Charts, fair tests and explaining what you found.

  1. 11How can a true chart still mislead me?Charts That Tell the Truth (and Ones That Don’t) · Misleading graphs
  2. 12How do I find out if the new thumbnail really helped?Running a Fair Test · A/B testing
  3. 13How do I explain what I found so people listen?Telling a Data Story · Data storytelling

Part V

Machines That Learn

How computers learn from examples, and how they get it wrong.

  1. 14How does a computer learn anything?Teaching With Examples · What machine learning is
  2. 15What should a car with 60,000 miles cost?Predicting Numbers · Linear regression
  3. 16How does my phone know which emails are spam?Sorting Into Categories · Classification
  4. 17How does a store know what “kind” of shopper I am?Finding Hidden Groups · Clustering
  5. 18Why does a model that aced the test flop in real life?Learned It or Memorized It? · Overfitting
  6. 19Why does AI get some people wrong more than others?Bias In, Bias Out · AI bias

Part VI

Modern AI

Neural networks, chatbots and the feed on your phone.

  1. 20What’s actually inside a neural network?Inside a Neural Network · Neural networks and deep learning
  2. 21How does a chatbot decide what to say next?How Chatbots Work · How ChatGPT works
  3. 22Why does my feed know what I want to watch?How Your Feed Works · Recommendation algorithms
  4. 23What do people who do this for a living actually do all day?AI in the Real World · What data scientists do

Finale

Your Turn

Grab a free dataset from Kaggle and explore it yourself in Google Sheets or a few lines of Python.

  1. 24Where do I get real data and what do I do with it?Your Turn · Your first data project with Python

How a lesson works

Five minutes. Something to play with. Something to say.

  1. 1

    Scene

    One of the crew runs into a question worth answering.

  2. 2

    Play

    You try the idea with your hands before anyone names it.

  3. 3

    Name it

    Then it gets its proper name.

  4. 4

    Details

    A couple of short cards, each one tied back to the question.

  5. 5

    Back to it

    You answer the question from the story.

  6. 6

    Say it

    You leave with a Talk Card: one sentence you could explain to anyone.

The used-car lesson, start to finish.

Talk Card · Module 15

Regression draws the best line through past data so you can predict a number, like a car’s price from its miles.

Learn it together

Every module ends with a Dinner Table Challenge, one question to ask whoever’s across the table. In the story that’s Maya and Nana. At your house it’s whoever’s there. It works the same for a teenager and a grandparent, and explaining something out loud is the fastest way to find out you get it.

Dinner Table Challenge · Module 1

Maya asks Nana whether she thinks her phone listens to her. Then Maya explains what a phone can figure out without listening at all. Your turn: ask someone at home.

Print the AI vocabulary sheet for your table

There’s a story running through it

Why did Maya’s 14th video blow up?

Maya runs a small gaming channel. Thirteen videos get about the same views each. Then the 14th takes off, and nobody can say why. Every module adds a clue, each of the crew rules something out, and the answer turns out to be something the spreadsheet never recorded.

12345678910111213#14?1516
Views per video on Maya’s channel, made up for the story
Joel Pettigrew

Who’s building this

Joel Pettigrew

Data, analytics and AI product leader

I’ve spent twenty years building AI, data and analytics products, and the teams that ship them. Data to AI started because I wanted my own kids to understand how this stuff works, and to help me build it. It’s a Pettigrew Lab project, so it’s a family one.

Read my resume

Before you ask

Fair questions

How does AI work?

Most AI learns from examples instead of following rules someone typed in. It’s shown thousands of cases with the right answer attached, finds the pattern, and uses that pattern to guess about new cases. The guesses are only as good as the examples, which is why the course starts with data.

How does ChatGPT work?

It predicts the next chunk of text, one piece at a time. Your words get split into tokens, each token becomes a list of numbers, and a model trained on a huge amount of writing picks a likely next token, adds it, and goes again. Likely isn’t the same as true, so it can sound sure and still be wrong.

Do I need to be good at math?

No. Every lesson works without a single formula: you drag a line, move a slider, and read what happened in plain words. If you want the math, each lesson has an optional Go deeper section with the formulas and the notation, and you can skip it forever without missing the point.

Who is it for?

Anyone who keeps hearing about AI and would rather follow the conversation than nod along. It’s written so a high schooler and a grandparent can take the same five-minute lesson and both come out able to explain it. No statistics background and no coding are assumed anywhere in it.

Is this about how to use ChatGPT?

Not really. Plenty of apps teach prompts. This one explains what’s underneath: the data, the statistics and how machines learn from examples, so the tools stop feeling like magic.

What does it cost?

You can start for free. The first part of the course is free in the app, and the used-car lesson on this page runs right now in your browser with nothing to install. The rest is a one-time unlock rather than a subscription, so you pay once and it stays yours.

Does the app collect my data?

No. There’s no account, no ads, no analytics and no tracking, and your progress stays on your phone. An app that teaches you how your data gets used shouldn’t be quietly collecting yours. The privacy policy says the same thing in plain words.

What happens after the last module?

The last module shows you where to find free datasets, how to explore one in a spreadsheet with no code, and how to read a few lines of Python in your browser.

Where do I get it?

It’s out. Get it from the App Store on iPhone and iPad, or from Google Play on Android.