# Lesson 1

Getting to Know You

• Let's work together to collect data and explore statistical questions.

### 1.1: Which One Doesn’t Belong?: Types of Data

Which one doesn’t belong?

Question A: How many potato chips are in this bag of chips?

Question B: What is the typical number of chips in a bag of chips?

Question C: What type of chips are these?

Question D: What type of chips do students in this class prefer?

Your teacher will assign you a set of 3 questions.

• Write another question of your own that will require data collected from the class to answer.
• For each of the 4 questions, write a survey question that will help you collect data from the class that can be analyzed to answer the question.
• Ask the 4 survey questions to 15 classmates and record their responses to collect data.
1. What is the question of your own that will require data collected from the class to answer?
2. What are the 4 survey questions you will ask your classmates?
3. Summarize the data for each question in a sentence or two and share the results with your group.
4. With your group, decide what the responses for question number 1 have in common. Then do the same for questions numbered 2 and 3.
5. Does the question you wrote fit best with the questions from number 1, 2, or 3? Explain your reasoning.
responder’s name question 1 response question 2 response question 3 response my question response

1. Find a news article that uses numerical data to discuss a statistical question.

2. Find a news article that uses categorical data to discuss a statistical question.

### Summary

Statistics is about using data to solve problems or make decisions. There are two types of data:

• Numerical data are expressed using a number. For example, to answer the question “How tall are the students in this class?” you would measure the height of each student which would result in numerical data.
• Categorical data are expressed using characteristics. For example, to answer the question “What brand of phones do people use?” you would survey several people and their answers result in categorical data.

The question that you ask determines the type of data that you collect and whether or not there is variability in the data collected. In earlier grades, you learned that there is variability in a data set if not all of the values in the data set are the same. These are examples of statistical questions because they are answered by collecting data that has variability:

• “What is the average class size at this school?” would produce numerical data with some variability.
• “What are the favorite colors of students in this class?” would produce categorical data with some variability.

These are examples non-statistical questions because they are answered by collecting data that does not vary:

• “How many students are on the roster for this class?” would produce numerical data that does not vary. There is only one value in the data set, so there is no variability.
• “What color is this marker?” would produce categorical data that does not vary. There is only one value in the data set, so there is no variability.

### Glossary Entries

• categorical data

Categorical data are data where the values are categories. For example, the breeds of 10 different dogs are categorical data. Another example is the colors of 100 different flowers.

• non-statistical question

A non-statistical question is a question which can be answered by a specific measurement or procedure where no variability is anticipated, for example:

• How high is that building?
• If I run at 2 meters per second, how long will it take me to run 100 meters?
• numerical data

Numerical data, also called measurement or quantitative data, are data where the values are numbers, measurements, or quantities. For example, the weights of 10 different dogs are numerical data.

• statistical question

A statistical question is a question that can only be answered by using data and where we expect the data to have variability, for example:

• Who is the most popular musical artist at your school?
• When do students in your class typically eat dinner?
• Which classroom in your school has the most books?