How_To_Be_Good_At_Math

272 STATISTICS •^ CARROLL DIAGRAMS

Carroll diagrams

A Carroll diagram shows how a set of data, such as a group of

people or numbers, has been sorted. Carroll diagrams sort data

using conditions called criteria (the singular is criterion).

A criterion is like a yes/no question.

Let’s use a simple criterion to sort

the group of 12 animals below. This

is the criterion we’ll use: “is the animal

a bird or not?”

To further sort our group

of animals using the

Carroll diagram, we can add

a new criterion: “is it a flying

animal or not?” To fit into any

box, an animal must now

meet two criteria.

This Carroll diagram uses our

bird/not a bird criterion to sort

the animals into two boxes. We

put all the birds into the box on

the left. Those animals that aren’t

birds go in the box on the right.

All the animals fit into

one box or the other

Animals that

are not birds

but can fly

Animals that are

birds and can fly

Animals that are

birds but can’t fly

Animals that

are not birds

and cannot fly

Ostrich

Butterfly

Swan

Duck

Pigeon Cat

Penguin

Horse Dog

Bat

Bee

Eagle

Flying

Not flying

Bird

Pigeon

Eagle

Swan

Duck

Penguin

Ostrich

Bird Not a bird

Pigeon

Duck

Penguin

Eagle

Swan

Ostrich

Butterfly

Cat

Bat

Bee

Dog

Horse

Butterfly

Bat

Bee

Dog

Horse

Cat

Not a bird

Carroll diagrams sort

data into boxes.

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