1. Classifying Variables

Description of the lesson:

Introduction: Think-pair-share – What does 'variable' mean? (LIT)

• Students discuss in pairs the definition of 'variable' given hints. These hints may include examples where the variable is identified. Pairs will then join other pairs to compare their definitions, and decide which one is most appropriate in the context of statistics. (WM: problem solving)
• Each group will share their definitions, and the class with the help of the teacher will co-construct a definition of variable with respect to statistics.

This activity appropriately introduces the focus of the lesson and acts as a warm-up to activate schema. Students might refer to the variables used in science, which would reinforce the general meaning of the word, benefiting their learning as they will encounter 'variable' again in algebra.

Activity: Brainstorm (LIT)

• The teacher asks scenarios in which students would need to investigate variables. Eg: "What variables might we consider when joining a sport/buying a phone/buying a pair of shoes?" In pairs, students write down as many variables as they can think of on post-it notes (each variable on a separate post-it).
• After 2 minutes, ask the students to try and separate their variables into two groups. They can decided the basis of their grouping, but the aim is for them to separate them into numerical and categorical variables. As students are familiar with qualitative and quantitative data, some groups may have organised it this way. When they have finished grouping, ask each group how they decided to group their variables. (WM: problem solving, communication, reasoning, justification)
• Ask students what they think numerical and categorical mean. Discuss and share definition. Then ask students if they haven't already to group their variables into numerical and categorical variables (AFL) (WM: understanding). For students who have already done so, they can try to think of any additional variables to add to their groups.
• Present examples of discrete and continuous variables and ask students for the difference between the two groups. Discuss definitions of discrete and continuous variables. Ask students to group their numerical variables further into discrete numerical and continuous numerical. (AFL) (WM: problem solving, understanding)

Extension: Separate the categorical variables further into ordinal and nominal variables.

This grouping activity allows students to organise their thinking and they will be able to clearly see the differences between groups and the commonalities within a group.

Conclusion: Flowchart (ICT optional)

• On mini whiteboards, groups or pairs construct a flowchart with definitions and examples of variables which students will then copy into their workbooks. (AFL) (WM: communicating, understanding)
• This can be also done individually on any mind-mapping program available online or using Microsoft Word for students to print out and hand in to the teacher. Refer to Additional Resources for online links.
• Example: