Introduction to Data Handling
Primary 4 · Mathematics
Introduction to Data Handling
Lesson 4 of 5
30 min
Let's begin
Ishimwe asked every pupil in P4 to name their favourite fruit. He wants to pin the results on the class wall so everyone can see them at a glance. "A table is good," says his teacher, "but a bar graph is even quicker to read."
| Fruit | Number of pupils |
|---|---|
| Banana | 9 |
| Avocado | 6 |
| Mango | 8 |
| Pineapple | 4 |
| Passion fruit | 3 |
| Total | 30 |
If the numbers are big, one line cannot stand for 1: the graph would be far too tall. Let each line stand for 2, 5 or 10 instead. Here each line stands for 5 cows:
Ubumwe's bar reaches the 40 line, so Ubumwe has 40 cows. Amahoro's bar reaches the 25 line, so Amahoro has 25 cows.
Tip
T-A-S-L before you finish: Title, Axes, Scale that starts at 0, Labels. A graph missing one of these is hard to read.
Work each one in your exercise book first. Then tap Show answer to check.
In the fruit graph, which fruit is the most popular?
Answer: Banana, the tallest bar, with 9 pupils.
How many pupils were asked in Ishimwe's survey?
Answer: 30, because 9 + 6 + 8 + 4 + 3 = 30.
Your biggest number is 48. Would a scale of 1 or of 10 be better?
Answer: A scale of 10 (or 5). With a scale of 1 you would need 48 lines.
In the cow graph, how many cows does Ituze have?
Answer: 15. Its bar reaches the 15 line.
Why must all the bars have the same width?
Answer: So that only the height shows the number. A wider bar would look bigger even if its number was not.
What you learned today
Sources and credits
The stories, Rwandan examples, diagrams and practice questions were written by Ganzaa.
Quick check
In the fruit graph, how many pupils chose mango?
