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How do we train a computer to make decisions?

Unit 3, Module 3.3

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Feature 1: Body Type

1=circular 2=oval 3=egg 4=wedge 5=triangle

The three fish on your activity sheet have the following body types:

In your activity sheet table, replace the question marks for the Body Type column with the correct body type number.

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Feature 2: Tail Fin Types

1=crescent 2=heart 3=hanger

The three fish on your activity sheet have the following tail fin types :

In your activity sheet table, replace the question marks for the Tail Fin column with the correct body type number.

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Feature 3: Dorsal Fin Types

1=lens 2=leaf 3=swept_forward 4=swept_back

The three fish on your activity sheet have the following Dorsal Fin types:

In your activity sheet table, replace the question marks for the Dorsal Fin column with the correct Dorsal Fin type number.

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Feature 4: Pectoral Fin Types

1=sharp_points 2=curved_points 3=smooth

The three fish on your activity sheet have the following Pectoral Fin Types:

In your activity sheet table, replace the question marks for the Body Type column with the Pectoral Fin Type number.

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Feature 5: Body Colors

1=Red

2=Pink

3=Yellow

4=Orange

5=Lime

6=Forest

7=Blue

8=Purple

The three fish on your activity sheet have the following body colors:

In your activity sheet table, replace the question marks for the Body Color column with the correct Body Color number

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Feature 6: Fin Colors

1=Red

2=Pink

3=Yellow

4=Orange

5=Lime

6=Forest

7=Blue

8=Purple

The three fish on your activity sheet have the following Fin types:

In your activity sheet table, replace the question marks for the Fin Color column with the correct Fin Color number

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What does it feel like to�be a machine learning algorithm?

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The human who is training you has provided you two fish, and told you that one lives on a reef, and the other does not.

Use these two fish to develop 5 rules that can decide if a fish lives on a reef or not on a reef.

Non-reef:

Reef:

REVISE THIS

Teacher Note - Here are two fish note that we can’t tell by just looking at the fish which is a reef dweller. But the training data will tell us. We are relying on the labels from the training data to tell us which fish is a reef dweller.

Look at the top right corner - we are listing all the feature where these two fish differ.

We will pick our first feature on the list and test that feature (see decision tree)

We are trying to come up with an explanation for the training data. We are trying to come up with a rule …Since we have so little data so far .. some of these will drop out as we see more data.

We have four pairs that Each one of these pair is a different way of using the features

If we choose the first feature, is it orange we conclude not reef

Anything other than orange is a reef dweller

If we choose the second feature
Take away - Note the pairs are not expressing the same rules. They are expressing alternative rules.
The two elements in each pair will produce different predictions for some fish.
There are 8 different rules that we are looking at.

Any rule could be our potential decision tree -

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The human has provided new training data!

Check these new fish with your rules! If a rule that you came up with no longer applies, change the text color to red so that we know not use it anymore.

If all of your rules are red, erase a rule and build a new rule.

Non-reef:

Reef:

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Here is another fish! Do your rules still work? Change / add what you need to your table! Remember to mark broken rules in red.

Non-reef:

Reef:

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Here is another fish! Do your rules still work? Change / add what you need! Remember to mark broken rules in red.

Non-reef:

Reef:

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Here is another fish! Do your rules still work? Change / add what you need! Remember to mark broken rules in red.

Non-reef:

Reef:

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Here is the last fish! Do your rules still work? Change / add what you need! Remember to mark broken rules in red.

Non-reef:

Reef:

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What was the rule that decided if a fish lived on a reef or not? Fill in the box for part 3.

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Turn your rule into a decision tree! For part 4, Double click the drawing to edit it.

Turn your rule into a question, and write it in the rectangle.

Where should the fish live if the answer is yes? Fill in the correct bubble with the correct location.

Where should the fish live if the answer is no? Fill in the correct bubble with the correct location.