Grade by Grade
D. Data · Two-Variable Data, Scatter Plots and Probability

Telling a Data Story: Infographics with Tables and Scatter Plots

D1.4 D1.3 D1.5 A1About 60 minutes
Learning goals
  • I can plan an infographic that tells the story of a two-variable data set.
  • I can include a table of values and a scatter plot with a title, labels, scales and a source.
  • I can add other useful information, like means, a description of the relationship, a headline and a takeaway.
  • I can give and use feedback to improve an infographic.

Words to know

infographic
A poster or page that combines graphs, tables, numbers, short text and pictures to tell a clear story about data.
headline
A short title that states the main message of the data, not just the topic.
takeaway
What the reader should remember or do after seeing the infographic.
audience
The people the infographic is made for.

Remember from Grade 7

Your Grade 7 infographics used tables and circle graphs to tell a story about one-variable data. In Grade 8 the star of the infographic is the scatter plot, with a table of values, because the story is about a relationship between two variables.

A story, not a pile of numbers

A good infographic answers one question in a way a busy reader can understand in 30 seconds. The soccer team manager wants parents to understand why the team needs more water on hot days. Here's what her infographic could include:

  • A headline that states the message: "Hotter Days, Thirstier Team" (not just "Water Data").
  • The scatter plot, with title, axis labels, scales and source.
  • The table of values, or the key rows from it.
  • Key numbers: the mean of each variable, the range, the number of practices.
  • A description of the relationship: strong positive, and any outliers.
  • A takeaway or decision: what parents should do.
  • Source and limits: where the data came from and how much of it there was.
Water bottles and an orange water cooler sit on a bench beside a soccer field on a sunny day, with players practising in the distance.
On a hot day, a team drinks more water at practice. Pairing each day's temperature with the amount of water used gives the two-variable data behind the manager's infographic. AI-generated image
Hotter Days, Thirstier TeamHow much water our soccer team drinks at practiceTemperature (°C) →Water (L) →Strong positive23.4°Cmean high14.7 Lmean waterAbove 25°C: packat least 17 LSource: team manager's records, 10 practices
A sketch of an infographic layout: a headline, a small scatter plot of the 10 practices, a box describing the relationship, two key means, a takeaway, and the source. A real infographic would show the full scatter plot with scales and the table of values too.
Worked example

Example 1: Finding the key numbers

Find the mean, median and range of each variable in the soccer data: temperatures 14, 17, 19, 21, 23, 25, 26, 28, 30, 31 (°C) and water 9, 10, 12, 12, 14, 15, 17, 18, 19, 21 (L).

  1. Mean temperature: 14 + 17 + 19 + 21 + 23 + 25 + 26 + 28 + 30 + 31 = 234. 234 ÷ 10 = 23.4°C.
  2. Mean water: 9 + 10 + 12 + 12 + 14 + 15 + 17 + 18 + 19 + 21 = 147. 147 ÷ 10 = 14.7 L.
  3. Medians (the values are already in order; average the 5th and 6th values): temperature (23 + 25) ÷ 2 = 24°C; water (14 + 15) ÷ 2 = 14.5 L.
  4. Ranges: temperature 31 − 14 = 17°C; water 21 − 9 = 12 L.

Mean high 23.4°C, mean water 14.7 L; medians 24°C and 14.5 L; ranges 17°C and 12 L. Pick the one or two numbers that help the story most, not all of them.

Temperature and Water Drunk at Practice10152025303505101520250Daily high temperature (°C)Water (L)Source: team manager's records, 10 practices
The full scatter plot for the infographic: 10 practices from (14°C, 9 L) to (31°C, 21 L).
Worked example

Example 2: Writing the headline and takeaway

Write a headline, a one-sentence description of the relationship, and a takeaway for the soccer infographic.

  1. Headline: short, states the message. "Hotter Days, Thirstier Team".
  2. Relationship: "There is a strong positive relationship: on hotter days, the team drinks more water." Add a number: "from 9 L at 14°C to 21 L at 31°C".
  3. Takeaway (decision): at the 5 practices of 25°C or more, the team drank 15 to 21 L, with a mean of 18 L (15 + 17 + 18 + 19 + 21 = 90, and 90 ÷ 5 = 18). At the 4 practices of 26°C or more it always drank at least 17 L. So: "When the forecast is above 25°C, pack at least 17 L, and extra on the hottest days."

Headline: Hotter Days, Thirstier Team. Relationship: strong positive, from 9 L at 14°C to 21 L at 31°C. Takeaway: pack at least 17 L when it's above 25°C.

Worked example

Example 3: Giving feedback

Jonah's first draft of a ball-bounce infographic has the headline "Ball Data", a scatter plot with no axis labels, 9 different fonts, and no source. Give him kind, useful feedback.

  1. Start with a strength: "Your scatter plot points are plotted accurately."
  2. Be specific about improvements: "Your headline could say the message, like 'Drop It Higher, It Bounces Higher.'" "Add axis labels with units (cm)." "Add a source line: who did the experiment and how many trials."
  3. Suggest design: "Using one or two fonts would make it easier to read."

Feedback that names a strength, gives specific next steps, and is about the work, not the person, helps Jonah improve. When you get feedback, decide which suggestions make your story clearer and use them.

Infographic checklist

  • Does the headline state the message?
  • Is there a scatter plot with title, axis labels, units, scales and source?
  • Is there a table of values (or the key data)?
  • Are the key numbers correct and useful?
  • Is the relationship described (strength, direction, outliers)?
  • Is there a takeaway or decision?
  • Are the limits stated (how many, when, who)?
  • Is it easy to read in 30 seconds?
Just for fun

An infographic that takes 10 minutes to read isn't an infographic. It's a novel with charts.

Hands-on activity

Make your own infographic

You need: a large sheet of paper (or a slide on a computer), markers or pencil crayons, a ruler, and two-variable data: your pendulum or ball-bounce data, your family height and foot length data, or the hot chocolate data from this unit.

  1. Decide your audience and your one main message.
  2. Draw the scatter plot carefully (title, labels, units, scales, source).
  3. Add the table of values.
  4. Calculate one or two key numbers (like the means).
  5. Write a headline, a relationship sentence and a takeaway.
  6. Add simple icons or pictures that match the data (a ball, a ruler, a cup).
  7. Show it to a family member for 30 seconds, then ask them what the main message was. If they can't say it, revise!

What to look for: someone who has never seen your data can tell you the relationship and the takeaway after a quick look.

Your turn

1

Which headline is better: "Temperature and Hot Chocolate" or "Colder Days, More Hot Chocolate"? Why?

2

Find the mean number of cups sold in the hot chocolate data: 62, 58, 55, 49, 47, 40, 38, 31, 30, 22.

3

Name three things an infographic about two-variable data should include.

4

Why include the source and the number of practices on the soccer infographic?

5

Write a relationship sentence for Jonah's ball data: drop heights 25 to 150 cm, bounces 15 to 88 cm, close to a straight line.

6

Find the median of the soccer water data: 9, 10, 12, 12, 14, 15, 17, 18, 19, 21.

More practice: warm-up

1

What is an infographic?

2

Which graph is the star of a Grade 8 two-variable infographic?

3

What is a takeaway?

4

Find the range of the temperatures 14 to 31°C.

5

True or false: an infographic should include every number you calculated.

More practice: on your own

1

Find the mean drop height and mean bounce height for Jonah's data: (25, 15), (50, 29), (75, 44), (100, 58), (125, 74), (150, 88).

2

The hot chocolate infographic is for the rink's volunteer staff. Write a useful takeaway.

3

A classmate's infographic has a circle graph of temperature and water. What feedback would you give?

4

Give two limits to put on the soccer infographic.

5

Why should the scatter plot on the infographic start the temperature axis just below 14°C (with a zigzag) instead of at 0°C?

Challenge

1

The manager adds an 11th practice: 33°C and 23 L. Find the new mean water amount. Does the relationship change?

2

Design a two-variable infographic question about your community (not from this lesson). Name the variables, the graph, two key numbers you'd include, and a possible takeaway.

3

A student wants to show both the relationship between temperature and water and how water use changed over the season. Suggest how to fit both in one infographic.

Check your understanding

Quiz

1.

Which is the best infographic headline?

2.

The temperatures sum to 234 for 10 practices. What is the mean?

3.

Which belongs in a Grade 8 two-variable infographic?

4.

What is the purpose of a takeaway?

5.

Which feedback is most helpful?

6.

Water: 9, 10, 12, 12, 14, 15, 17, 18, 19, 21. What is the median?

For parents and teachers

Big idea: The Ontario curriculum (D1.4) asks Grade 8 students to create an infographic about a data set, representing the data in tables and scatter plots, and including other relevant information that helps tell a story about the data. Your child will also practise D1.3 (graph features) and D1.5 (describing relationships).

Common difficulties:

  • Headlines that name a topic instead of a message.
  • Too much clutter: every number, many fonts, decorations that don't match the data.
  • Graphs missing labels, units, scales or a source.
  • Forgetting limits (how many, when, who).

How to help: Be the "30-second reader": look at the infographic for 30 seconds and say what you think the message is. If you can't, help your child revise. Model kind, specific feedback (a strength plus a next step). This builds A1 skills in communication and giving and receiving feedback.