Data is a collection of facts, numbers, or information. Data handling means collecting, organising, and reading data to answer questions.
Collecting Data
- We collect data by counting, asking questions (surveys), or observing. The result is often shown as a tally.
- Each tally mark | = 1. Four marks with a diagonal cross |||| = 5. This makes counting easy.
Pictograph
- A pictograph uses pictures or symbols to show data. Each symbol stands for a fixed number.
- Always check the key (scale) — for example, one star symbol = 5 students.
Bar Graph
- A bar graph uses rectangular bars. The length of the bar shows the amount. One axis shows categories; the other shows numbers (the scale).
- Read the scale carefully before reading the height of a bar.
Reading a Table
A table organises data in rows and columns. Use it to compare values quickly.
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Tally for fruits sold: Apples: |||| || (7), Mangoes: |||| (5), Bananas: |||| |||| | (11). Which fruit sold the most?
Bananas with 11 sold most.
In a pictograph, each apple symbol = 3 students. Class A has 4 symbols. How many students chose apples in Class A?
4 x 3 = 12 students
A bar graph shows: Red = 8 students, Blue = 12, Green = 5, Yellow = 10. How many more students prefer Blue than Red?
12 - 8 = 4 more students
Total students from the bar graph above?
8 + 12 + 5 + 10 = 35 students
In a tally chart, games played: Cricket: 14, Football: 11, Badminton: 8, Chess: 7. What fraction of students play Cricket?
Total = 14 + 11 + 8 + 7 = 40. Cricket fraction = 14/40 = 7/20
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Common mistakes
- Ignoring the key in a pictograph — always multiply the number of symbols by the key value.
- Misreading the bar graph scale — if scale is "by 5s" and the bar reaches 3, the value is 3 x 5 = 15.
Summary
Tally marks, pictographs, and bar graphs all help us organise and display data. Always check the key or scale before reading values. Use addition and subtraction to compare and find totals.