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Class 7 Data Visualisation and Analysis: cheat sheet
CBSE Computational Thinking and AI. Charts make data easy to read. Choose a bar, line or pie chart to suit the data, and sum it up with mean, median, mode and range.
Key ideas
- A bar graph compares separate groups, like books read by each class.
- A line graph shows how one value changes over time; the steepest rise is the biggest increase.
- A pie chart shows parts of one whole; all the slices add up to 360°.
- The mean shares the total equally; the median is the middle value once the data is in order.
- The mode is the most common value; the range measures how spread out the data is.
- Reading changes month to month (+ or −) shows trends better than the values alone.
Remember
| Mean | sum of values ÷ number of values |
| Median (odd count) | the middle value after sorting |
| Range | largest − smallest |
| Pie chart angle | part ÷ total × 360° |
| Example | 9 of 36 children walk → 9 ÷ 36 × 360° = 90° |
Watch out
- Finding the median without putting the data in order first.
- Using a pie chart for change over time: use a line graph.
- Picking the month with the highest value instead of the biggest rise from the month before.
Worked example
(a) Goals scored in 5 matches: 15, 21, 12, 16, 21. What is the mean? (b) Goals scored in 5 matches: 23, 24, 4, 19, 14. What is the median?
Working: (a) 85 ÷ 5; (b) in order: 4, 14, 19, 23, 24; the middle one
Answer: (a) 17; (b) 19
Practise Data Visualisation and Analysis
Revise with this page, then practise: every Data Visualisation and Analysis sheet in the app is new, with an answer key and working.
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