Statistics & Data
Learn how to read bar graphs, pictographs, and calculate the mean (average) from a data set.
Types of Graphs
Graphs help us see data clearly. There are different types, and each is useful in different situations.
Bar Graph
Uses bars of different heights to compare amounts. Each bar represents a category.
Pictograph
Uses pictures or symbols to represent data. A key tells you what each symbol means.
Apples: 🍎🍎🍎 = 6
Bananas: 🍎🍎 = 4
Oranges: 🍎🍎🍎🍎 = 8
Key: 🍎 = 2 pieces of fruit
When to use what? Bar graphs are great for comparing categories. Pictographs are fun and easy to read when numbers are small and round.
Reading a Bar Graph
When reading a bar graph, always check the title, the axis labels, and the scale.
Example: Favourite Sports in Year 5
Soccer
10
Cricket
6
Swimming
8
Tennis
4
From this graph: Soccer is the most popular (10 students). Tennis is the least popular (4 students). The total is 10 + 6 + 8 + 4 = 28 students.
Calculating the Mean (Average)
The mean is the most common type of average. It tells you what each person “would get” if everything were shared equally.
Mean = Total of all values ÷ Number of values
Example: Find the mean of 4, 6, 8, 10, 2
Step 1: Add all values: 4 + 6 + 8 + 10 + 2 = 30
Step 2: Count the values: 5 numbers
Step 3: Divide: 30 ÷ 5 = 6
Mean = 6
Knowledge Check
Select the correct answer for each question. Questions get harder as you go!
Question 1
In a pictograph, ★ = 5 students. If “Swimming” has 3 stars, how many students chose swimming?
Question 2
A bar graph shows: Cats = 12, Dogs = 18, Fish = 6. Which pet is most popular?
Question 3
Find the mean of: 2, 4, 6
Question 4
A bar graph shows: Mon = 5, Tue = 8, Wed = 3, Thu = 8, Fri = 6. How many more items were sold on Tuesday than Wednesday?
Question 5
Find the mean of: 10, 5, 15, 10
Question 6
In a pictograph, each smiley face = 4 students. “Reading” shows 5 smiley faces and “Sport” shows 3 smiley faces. How many more students chose Reading than Sport?
Question 7
The total of 5 numbers is 45. What is their mean?
Question 8
Find the mean of: 7, 3, 11, 5, 9
Question 9
Four friends scored 8, 6, 10, and 12 goals this season. A fifth friend joins and the mean becomes 8. How many goals did the fifth friend score?
Question 10
A bar graph shows ice cream sales: Mon = 15, Tue = 20, Wed = 25, Thu = 10, Fri = 30. What is the mean daily sales?
Key Concepts Summary
- ●Bar graphs use bars to compare categories. Taller bar = larger value.
- ●Pictographs use symbols. Always check the key to know what each symbol represents.
- ●Mean = Total of all values ÷ Number of values.
- ●Always check the title, labels, and scale when reading any graph.