Minds On
Circling the issue
Examine the following graph.
Student Success
Think-Pair-Share
Answer the following questions about the circle graph. Throughout this learning activity, you can record your ideas digitally, orally, or in print.
1. What is the graph about?
2. What do you notice about it?
3. Estimate how many people chose the most popular category.
4. Why can you not say the actual percentage or number?
5. What information is missing?
Note to teachers: See your teacher guide for collaboration tools, ideas and suggestions.
Press ‘Answers’ to check how you did.
1. The graph is about the amount of time people spend working on papers.
2. I notice that there is a legend/key and that each of the categories in the legend is represented in the circle. I notice that orange is the biggest piece.
3. I think that around 50% of people are “Figuring out how much time I have left.”
4. There are no numbers. I would have to get a protractor and figure out what percent each piece was to be able to figure out the percent of each section. Even then, I still don’t know how many people this is about.
5. We don’t know the total number of respondents.
Action
Exploring the circle graph
A circle graph is a type of a graph that uses a circle broken up into “slices” or “wedges” to show the size of each category.
Circle graph 1: Month of Birth
Investigate the circle graph called “Month of Birth.” The data was collected by surveying all the students at Parkview School.
Student Success
Circle graph ideas
Answer the following questions about the circle graph. Record your ideas and if possible, share them with a partner.
1. What is the title of this circle graph?
2. What is the source of the data in this circle graph?
3. In which month were the most students born? In which month were the fewest born?
4. How is the information about each segment given?
Note to teachers: See your teacher guide for collaboration tools, ideas and suggestions.
Press ‘Answers’ to check how you did.
1. The title is Month of Birth: Students at Parkview School.
2. The source of the data is all the students in Parkview School.
3. The most students were born in April. The fewest were born in September.
4. Each segment has a label and a percentage.
Circle graph 2: Weather Systems During November
Investigate the following circle graph titled “Weather systems during November.” The data was organized by a weather network.
Student Success
November weather
Answer the following questions about the “Weather Systems During November” circle graph. Record your ideas digitally, orally, or in print. If possible, share your ideas with a partner.
1. How many weather systems are represented on this graph?
2. Which weather system occurs the most during the month of November?
3. Name the three weather systems that dominate in November.
Note to teachers: See your teacher guide for collaboration tools, ideas and suggestions.
Press ‘Answers’ to explore how you did.
1. There are five weather systems represented on this graph.
2. The weather system that occurs the most during the month of November is Rainy.
3. The three weather systems that dominate are Rainy, Sunny, and Cloudy.
Brainstorm
What’s missing?
While there is data that can be explored from a circle graph, other data is missing. Brainstorm what could be missing. Think about what the data does not help us understand. Share your ideas with a partner, if possible.
Press ‘Answer’ to compare your ideas with a suggested response.
For example, this data does not help us understand the following:
- The number of days that each weather system has occurred.
- Why these weather systems are occurring.
- If there are similarities between the weather during November and other months.
Student Success
Circle Graph ideas
You have now examined several circle graphs. Come up with some ideas about the following questions, and use a method of your choice to record them. If possible, share your ideas with a partner.
- When do you think it is appropriate to use a circle graph?
- What are the possible advantages and disadvantages of circle graphs?
Note to teachers: See your teacher guide for collaboration tools, ideas and suggestions.
Press ‘Table’ to compare your answers with some suggestions.
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Circle graphs are appropriate when we need to… visualize information and data sets easily display the results of a data set compare the parts of a whole deal with percentages that add up to 100% |
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Circle graphs: Advantages |
Circle graphs: Disadvantages |
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Able to show total percentages. Display information in an appealing manner. Easy to interpret. |
Hard to compare two sets of data. Numerical data not very exact. Not great for data sets with many categories (good for about 3-7 categories). Can only be used to display discrete data. |
Activity
Examine each of the following topics. Decide if it is more appropriate to display data for this topic in a circle graph or another type of graph. Select the correct answer, then press ‘Check Answer’ to check how you did.
Creating a circle graph
Press on the following steps to learn how to create a circle graph.
We’ll use this data set as an example:
|
Genre of TV show |
Responses |
|
Drama |
8 |
|
Comedy |
12 |
|
Action |
8 |
|
Sci-Fi |
2 |
|
Reality TV |
10 |
|
Total |
40 |
To convert a value into a percent, we need to know the total number of responses (40 in this case). This is our denominator. We divide each of the categories by 40 to find out what percentage of the whole circle it represents.
|
Genre of TV show |
Responses |
Percentage |
|
Drama |
8 |
8 ÷ 40 = 0.2 = 20% |
|
Comedy |
12 |
12 ÷ 40 = 0.3 = 30% |
|
Action |
8 |
8 ÷ 40 = 0.2 = 20% |
|
Sci-Fi |
2 |
2 ÷ 40 = 0.05 = 5% |
|
Reality TV |
10 |
10 ÷ 40 = 0.25 = 25% |
|
Total |
40 |
100% |
We need to know how many degrees (how big) each “slice” needs to be. Recall that a circle is 360 degrees.
Use this formula to calculate the number of degrees for each slice:
(Number of items in category divided by the total number of values in the data set) x 360 °
|
Genre of TV show |
Responses |
Percentage |
Degrees |
|
Drama |
8 |
8 ÷ 40 = 0.2 = 20% |
(8 ÷ 40) × 360° = 72° |
|
Comedy |
12 |
12 ÷ 40 = 0.3 = 30% |
(12 ÷ 40) × 360° = 108° |
|
Action |
8 |
8 ÷ 40 = 0.2 = 20% |
(8 ÷ 40) × 360° = 72° |
|
Sci-Fi |
2 |
2 ÷ 40 = 0.05 = 5% |
(2 ÷ 40) × 360° = 18° |
|
Reality TV |
10 |
10 ÷ 40 = 0.25 = 25% |
(10 ÷ 40) × 360° = 90° |
|
Total |
40 |
100% |
360° |
You can make your circle graph in your notebook or create it online. Don’t forget your title, labels, and legend!
Activity
Checklist
Use the following checklist to make sure your circle graph has everything it needs. Complete Checklist: Circle Graph in your notebook or use the following fillable and printable document. If you prefer, use another method to record the information.
Press the ‘Activity’ button to access Checklist: Circle Graph.
Checklist: Circle Graph
Press ‘Answer’ to reveal an example of a circle graph.
Description
A circle graph titled "Favourite TV show genres in grad 7" divided into 5 sections according to the following percentages: Comedy 30%, Reality TV 25%, Drama 20%, Action 20%, Sci-fi 5%.
Consolidation
Thinking about circle graphs
Circle graphs have an important role in data analysis.
Consider the circle graphs provided and describe the graphs in fractions instead of percentages. What kind of data would it be appropriate to describe using percentages or fractions?
Test Your Skills!
Design a lesson
Design a recording or note to teach others about circle graphs.
Complete Circle Graph: Basics in your notebook or use the following fillable and printable document. If you prefer, use another method to record your ideas.
Press the ‘Activity’ button to access Circle Graph: Basics.
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Circle Graph: Basics |
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What needs to be included on all circle graphs? |
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How can circle graphs support the analysis of data?
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What are the limits for using circle graphs?
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Reflection
As you read the following descriptions, select the one that best describes your current understanding of the learning in this activity. Press the corresponding button once you have made your choice.
I feel…
Now, expand on your ideas by recording your thoughts using a voice recorder, text-to-speech, or writing tool.
When you review your notes on this learning activity later, reflect on whether you would select a different description based on your further review of the material in this learning activity.
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