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AI Explorers 3-5 / Week 04 / Tuesday
2/6
Week 04 · Features and Models

Tuesday

A tree of questions
// Clues, questions and trees
⏱ about 15 min

Tuesday: A Tree of Questions

Rocket writes questions on sticky notes. "Is it green? Is it lumpy? Does it have a handle?"

The notes pile up everywhere. "Which question comes first?" he groans.

Raven sorts them. "What do you notice? Some questions split the photos into two groups."

Nova hovers above the notes. "Here is a hint," she says. "Start with the question that splits the pile best."

What is a decision tree?

A decision tree is a model made of yes or no questions.

You start at the top question. Your answer sends you down a branch.

Each branch leads to another question or to an answer.

Here is the crew's first sorting model for the photo pile.

Question 1: Does it have a handle?
Yes
Label it tool.
No
Question 2: Does it have leaves? Yes: label it plant. No: label it rock.

Let us follow one photo. It is a green stem with leaves.

Handle? No
↓
Leaves? Yes
↓
Label: plant
FOLLOW THE TREE
  • Read the question.
  • Tap your answer.
A photo shows a gray lump with no handle and no leaves. Which label?
A photo shows a hammer with a handle. Which label?
A photo shows a fern with lots of leaves. Which label?
FOLLOW A PLANT PHOTO THROUGH THE TREE
  • ?Go to question 2.
  • ?Does it have leaves? Yes.
  • ?Does it have a handle? No.
  • ?Label it plant.
  • ?Start at question 1.
WHY THIS EXERCISEA decision tree is followed one question at a time, from the top.

Every path ends in an answer

Our tree has 2 questions and 3 answers: tool, plant and rock.

Any photo can follow it from the top to a label.

The tree does not think. It just follows the questions.

StatementTrue or false?
A decision tree uses yes or no questions.?
You can start at any question you like.?
Our tree has 3 answer labels.?
The tree thinks about each photo like a person.?
WHY THIS EXERCISEA decision tree is a model of steps. It does not think like a person.
A model made of yes or no questions is a decision ____.
How many questions are in the crew's tree?
One path in a tree is called a ____.
A photo shows a rake with a handle. Which label does the tree pick?
WHY THIS EXERCISEYes to a handle leads straight to the tool label.
FOLLOW A ROCK PHOTO
  • Tap a card.
  • Then tap its spot.
1Question 1
2Question 2
3Answer
WHICH QUESTION FIRST?
  • Read the question.
  • Tap your answer.
What does question 1 do to the pile?
A photo gets the plant label. How many questions did it answer?
Try it
Copy the crew's tree onto paper with boxes and arrows.
Make up a new photo. Follow it through your tree with your finger.

You followed a real decision tree! Tomorrow you build and test one in the lab.

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