← Machine Learning & Deep Learning

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Two Groups or Many Groups

Sometimes sorting is simple: this pile or that pile. Heads or tails. Pass or fail. But sometimes you need many piles — one for every letter of the alphabet, or one for every animal in the zoo. Sorting machines can handle both! Let's look at the difference.

Two Groups: Yes or No

The simplest sort divides things into exactly two groups. We call this a yes-or-no sort, or a two-group sort. Examples you might recognize: - Is this email spam? Yes or No. - Is this photo a hot dog? Yes or No. - Did this student pass the quiz? Yes or No. The machine only has to pick between two choices. That makes the job a little simpler.

The Big Idea

A two-group sort asks: which of two choices is this? A many-group sort asks: which of many choices is this? Sorting machines can do both.

Now imagine you want to sort photos of animals — not just dog or not-dog, but dog, cat, bird, fish, or rabbit. That is a five-group sort. The machine still studies labeled examples and finds patterns. But now it has to learn what makes a dog different from a cat AND different from a bird AND different from a fish AND different from a rabbit. It needs more examples for each group to do a good job. The more groups you have, the more labeled examples you usually need.

Match each sorting word to what it means.

Terms

Two-group sorting
Many-group sorting
A group
A label
Sorting machine

Definitions

A set of things that belong together
The name that tells which group a thing belongs to
Placing things into three or more groups
A machine taught to put things into the right group
Placing each thing into one of just two groups

Drag terms onto their definitions, or click a term then click a definition to match.

Real sorting machines in the world use both kinds. A spam filter uses two groups. A speech-recognition machine that hears you say a word and figures out which word it is uses many groups — one for every word in the language! The choice between two groups or many groups depends on the job you need done.

Start Simple

When you design a sorting job, start with as few groups as you need. Two groups are easier to label and easier to check than ten. You can always add more groups later.

A machine decides if a photo shows a cat or a dog. How many groups is that?

Which sorting job would need MANY groups?

Design Your Own Sort

  1. Think of a sorting job you would like a machine to do.
  2. Decide: will it sort into two groups or many groups?
  3. Write down the name of each group.
  4. List three examples that belong in each group.
  5. Share your sort design with a friend or family member and see if they agree with your groups.
  6. Talk about why you chose two groups or many groups.
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