Types of Data

• When we are interested in finding out more about something, we start asking questions about it. Some questions have answers that are words or categories, for example, What is your favorite sport? Other questions have answers that are numbers, for example, How many inches tall are you?

Task:

• In your group there are two strips. Read those strips as a group and decide whether your question has words/categories or numbers as answers.

• You will have three minutes to decide. • When the music stops have one member of your

team place your strips under the categorical or numerical data column and be prepared to explain your choice.

Category and Number Questions

• The data you collect in response to a question you ask may be numbers or words.

• Categorical Data- data that are words or categories. Categorical data are usually not numbers. If you asked people in which month they were born or what kinds of pets they have, their answers would be categorical data.

• Numerical Data- data that are numbers. If you asked people how tall they are or how many pets they have, their responses would be numerical data.

Problem 2.1

• Think of some things you would like to know more about. Then, develop some questions you could ask to gather information about those things.

• A. Write two questions that have categorical data as answers.

• B. Write two questions that have numerical data as answers.

Problem 2.1 Follow-Up

• Is it possible to find the mode of a set of categorical data? Explain your answer.

Do you have a pet?

Cats

                                                             

        dogs          

                              

Fish

Birds

                          

snakes

Other Pets

Investigation 2.2Counting Pets

The pets people have often depend on where they live. People who live in cities often have small pets, while people who live on farms often have large pets. People who live in apartments are sometimes not permitted to have pets at all. It is fun to find out what kinds of pets people have.

One middle class gathered data about their pets by tallying students’ responses to these questions:

•What is your favorite kind of pet?

•How many pets do you have?

The students’ questions produced two kinds of data. When students told what their favorite pets were, their responses were categorical data. When the students told how many pets they had, their responses were numerical data.