Review the key concepts, formulae, and examples before starting your quiz.
🔑Concepts
Discrete Data: Data that can only take specific values (e.g., number of students, shoe sizes) and is often shown in bar charts or pictograms.
Pictograms: A way of representing data using pictures or symbols. Every pictogram must include a 'Key' to explain what each symbol represents.
Partial Symbols: In pictograms, a half or quarter of a symbol represents a fraction of the value defined in the key (e.g., if one circle = 4, half a circle = 2).
Bar Charts: Graphs where the height or length of the bars represents the frequency. Bars must be of equal width with equal gaps between them.
Axes and Scaling: The vertical axis (y-axis) usually shows the frequency, while the horizontal axis (x-axis) shows the categories. Choosing an appropriate scale (e.g., intervals of 2, 5, or 10) is crucial.
The Mode: In bar charts and pictograms, the mode is the category with the highest bar or the most symbols.
📐Formulae
💡Examples
Problem 1:
In a pictogram, a symbol of a book represents 8 books. If the 'History' category shows 3 full book symbols and one half-book symbol, how many history books are there?
Solution:
28 books
Explanation:
Calculate the value of full symbols first: . Then calculate the half symbol: . Add them together: .
Problem 2:
A bar chart shows that 15 students like Blue, 10 like Red, and 12 like Green. How many students were surveyed in total?
Solution:
37 students
Explanation:
To find the total number of students, sum the frequencies of all categories: .
Problem 3:
On a bar chart, the 'Apples' bar reaches 18 and the 'Oranges' bar reaches 7. How many more apples are there than oranges?
Solution:
11
Explanation:
Subtract the frequency of Oranges from the frequency of Apples: .