Class 6 ยท Maths ยท Ganita Prakash
Chapter 4 ๐
Chapter 4 ๐
Data Handling and Presentation
Quick, colourful revision notes โ easy to read before your test!
Chapter Contents
4.1 Collecting & Organising Data
Data โ any collection of facts, numbers, measures or observations that gives us information about something.
Raw data (like a long list of names and choices) is hard to read at a glance. We organise it using tally marks to make it easy to count.
@edugrown ๐ @edugrown ๐ @edugrown ๐
@edugrown ๐ @edugrown ๐ @edugrown ๐
Fig 1: Tally marks โ every 5th mark crosses the previous four, making groups of 5 easy to count
Frequency โ the number of times something occurs in the data (e.g. 9 students chose Gulab Jamun โ frequency = 9).
4.2 Pictographs
A pictograph represents data using pictures/symbols, where each symbol stands for a fixed number of items โ shown in a key (e.g. ๐ง = 10 children).
@edugrown ๐ @edugrown ๐ @edugrown ๐
@edugrown ๐ @edugrown ๐ @edugrown ๐
Fig 2: A half symbol means half the value โ here, half of 10 = 5
"Always" has 5 full symbols โ 5 ร 10 = 50 children.
"Sometimes" has 2 full + 1 half symbol โ (2ร10) + 5 = 25 children.
"Sometimes" has 2 full + 1 half symbol โ (2ร10) + 5 = 25 children.
When numbers are large, one symbol can stand for many units (5, 10, 100...) โ this keeps the pictograph compact and easy to draw.
4.3 โ 4.4 Bar Graphs
A bar graph uses bars of uniform width (equally spaced) to show data โ the length/height of each bar represents its value.
@edugrown ๐ @edugrown ๐ @edugrown ๐
@edugrown ๐ @edugrown ๐ @edugrown ๐
Fig 3: Bar graph of students absent in each class (I to VIII)
From this graph: Class VIII had the most absentees (7), and Class V had full attendance (0 absent) โ both readable in one glance!
Bar graphs work well for large amounts of data โ drawing a pictograph for hundreds of items would take too long and too much space.
4.5 Drawing Good Graphs
A good graph needs: a clear title, labelled axes, a key/scale (if 1 unit โ 1 item), uniform bar widths and equal spacing โ so anyone can read it correctly without confusion.
Choosing the scale matters! If a bar graph's scale is drawn unevenly or misleadingly, it can make small differences look huge (or hide big differences) โ always check the scale before trusting a graph you see in the news!
๐ฏ Quick Summary
- Data = collected facts/numbers that give information; organise it using tally marks to find frequency.
- Pictograph = data shown using symbols/pictures; check the key to see what one symbol is worth.
- Bar graph = data shown using bars of uniform width and equal spacing; height/length = value.
- Bar graphs suit large data better than pictographs (faster and more compact to draw).
- A good graph always has a title, labelled axes, and a clear key/scale.
โ๏ธ Notes by @edugrown โ happy revising! ๐