Year level: 7

Strand: Statistics

Lesson length: 60 mins

In this first of two lessons, students acquire data as they conduct a sleep audit over two weeks to test hypotheses regarding improving sleep quality.

In a second lesson, Sleepy statistics: Part 2, students will represent the data using a back-to-back stem-and-leaf plot and draw conclusions based on statistical analysis.

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

Numeracy:

Digital Literacy:

Critical and Creative Thinking:

Related subject areas

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

The following is a mid-sequence opportunity for ongoing assessment for this lesson.

If time allows, students complete the mid-sequence Exit slip (slide 13 from the teacher’s slides) in the remainder or the lesson or as a homework task.

Note: Download, print and cut beforehand. There are three slips per page.

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.

Prior to this lesson, it is assumed 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.

What you need:

Learning goals

Learning intention

  • We will learn how to create and interpret a stem-and-leaf plot.
  • We will interpret and use data displays to compare datasets.
  • We will learn how different bedtime behaviours affect the quantity and quality of sleep, and understand the importance of statistical analysis in real-world data representation.

Success criteria

By the end of this lesson, students can:

  • record and organise data in a table
  • create a stem-and-leaf plot by hand
  • calculate mean, median and range accurately from a stem-and-leaf plot.

Why are we learning about this?

We live in a data-driven world, where statistics are everywhere and graphs are a helpful way to summarise and visualise data. Understanding and interpreting graphs is an important skill that allows us to quickly interpret and analyse information in real-world situations. Understanding sleep patterns is crucial for health and wellbeing. By statistically analysing personal data, we can make informed decisions on daily habits, promoting healthier lifestyles.

Learning hook 15 mins

Important note: This lesson series can be structured over a two and a half week period to allow for the collection of data. The learning hook below takes about 15 minutes to deliver with the teacher’s slides. Deliver this a week before this lesson is scheduled, so students can collect Week 1 sleep data. At the end of this lesson, you will instruct students to collect Week 2 data, which will have a slight change of instruction.

Iteration: If time is short and to reduce cognitive load, combine lesson with students creating two different stem-and-leaf plots for the two weeks of data (rather than a back-to-back stem-and-leaf plot). Remove the two-column graph created using a spreadsheet.

Learning hook

  • Hand out sticky notes (or squares of paper) and ask students to write down how long they think they slept last night in hours and minutes.
  • Ask the students to stand up with their papers or sticky notes and stand in a long line in increasing order. The teacher notes the highest and lowest values on the board and students return to their seats.
  • Ask students to think for 30 seconds about how much sleep they think they should get each night, and then tell their neighbour.
  • Bring up slide 2, which shows that ‘Adolescents are only getting between 6.5 and 7.5 hours of sleep on school nights’ and lead a discussion about how much sleep students should get, what affects our sleep, and why sleep is important for health.
  • Distribute the Sleep diary and instructions to students and use slides 3 and 4 to explain how to keep a sleep diary over the next week. Remind students about filling out the diary each lesson during the week.
  • If students ask why are they are keeping a sleep diary, show them the learning intentions on slide 5, and make connections with the task in your class discussion.

Explore 30 mins

Stem-and-leaf plots

  • Hand out more sticky notes and ask each student to note their date of birth ignoring the month and year, for example, a student born on 17 May writes 17, a student born on 28 February writes 28. Explain that we are going to create a new type of graph showing their birthdates.
  • Ask students to stick their notes on the whiteboard in rows. Place the notes in groups – 0–9, 10–19, 20–29 and 30–31, but in no order. Ask how the data would be better shown and elicit the idea of ordering the data. Ask a couple of student volunteers to reorder the data.
  • Draw a stem-and-leaf template on the whiteboard with 0 to 3 on the stem and demonstrate, with student assistance, how to add the data to the stem-and-leaf plot.
  • Explain the use and construction of a stem-and-leaf plot, using slides 6–9 if desired. It is important that the students gain familiarity with a double-digit stem as this will be required for their sleep survey data.
  • Use questioning to scaffold the students trying to find the range, mean, median and mode from the stem-and-leaf plot created in the Introduction.
  • Observe students’ work and use questioning/feedback to correct any misunderstandings.

Individual activities

Summary and reflection 15 mins

  • Reserve 10 minutes to summarise the key features of a stem-and-leaf plot. Go through slides 10 to 12, which are about sleep and sleep hygiene. Slide 11 gives the sleep diary instructions for Week 2 where students make one change to their daily sleep practices.
  • Remind students to record their sleep data every night.