Year level: 7

Strand: Statistics

Lesson length: 60 mins

In this second of two lessons, students represent their acquired sleep data using a back-to-back stem-and-leaf plot and draw conclusions based on statistical analysis.

In the previous lesson, Sleepy statistics: Part 1, students acquire data as they conduct a sleep audit over a two-week period.

Sleepy statistics: Part 2 Image

Achievement standard

By the end of Year 7, students plan and conduct statistical investigations involving discrete and continuous numerical data, using appropriate displays. Students interpret data in terms summary statistics.

Content descriptions

Students create different types of numerical data displays including stem-and-leaf plots using software where appropriate; describe and compare the distribution of data, commenting on the shape, centre and spread including outliers and determining the range, median, mean and mode. AC9M7ST02

Students plan and conduct statistical investigations involving data for discrete and continuous numerical variables; analyse and interpret distributions of data and report findings in terms of shape and summary statistics. AC9M7ST03

General capabilities


Digital Literacy:

Critical and Creative Thinking:

  • Interpret concepts and problems (Level 5),
  • Draw conclusions and provide reasons (Level 5)
  • Develop questions (Level 5)

Related subject areas

Science (AC9S7I02), Health and Physical Education (AC9HP8P10)

The formative assessment task below is an interesting way to evaluate student engagement in the whole investigation and highlight whether they have reached a deeper understanding of the concepts for this lesson.

Students complete a Frayer model for a stem-and-leaf plot. Download the handout and distribute it to students, or ask them to draw up the diagram in their exercise books to complete the task.

It is expected that students have:

  • a basic understanding of data representation methods such as tables
  • an ability to calculate time differences, for example, finding the difference between 9.45pm and 6.50am and converting times in hours and minutes to minutes
  • an ability to calculate mean, median and range for a dataset
  • an understanding of place and place value.

Some students may:

  • think all forms of data representation can be used interchangeably
  • find keeping consistent data recording difficult
  • experience difficulty using digital spreadsheets.

The following interventions are suggested. Teachers can:

  • highlight the purpose and effectiveness of different graphical representations – for instance, asking students what kind of data a stem-and-leaf plot could be effectively used for (categorical data, single/double-digit numerical data) and highlighting how other graphs, such as pie charts, might be a poor choice
  • check in with students each lesson to remind them to update their sleep diaries and consider emailing parents to remind them to support their children in completing the diary
  • model how to input data into software and generate graphs. Spreadsheets are pre-populated with inbuilt calculations in hidden tabs.

What you need:

  • Lesson plan (Word)

  • Teacher's slides (PowerPoint

  • Frayer model worksheet (Word)

  • Sleepy statistics bar graph spreadsheet (Excel)

  • Sleep diaries filled in by students

  • Computers or Tablets with access to Excel