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| source: ncert_exercises |
| topic: statistics |
| class_level: class_9 |
| chapter: ch12 |
| exercise: ex12.1 |
| difficulty: beginner |
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| Class 9 | Ch12: Statistics | Exercise 12.1 |
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| Key Concepts: |
| - Primary data: collected directly by investigator. |
| - Secondary data: collected from existing sources. |
| - Raw data: data before organisation. |
| - Frequency: number of times a value occurs. |
| - Class interval: range of values grouped together. |
| - Class width = Upper limit - Lower limit. Midpoint = (Upper+Lower)/2. |
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| Q1. A survey conducted by an organisation for the cause of illness and death among women between 15-44 years age group gave the following data. Draw a bar graph. |
| Reproductive health conditions: 31.8%, Neuropsychiatric conditions: 25.4%, Injuries: 12.4%, Cardiovascular conditions: 4.3%, Respiratory conditions: 4.1%, Other causes: 22%. |
| Answer: Draw bar graph with diseases on x-axis and percentages on y-axis. Each bar height = percentage given. ✅ |
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| Q2. The following data on the number of girls per 1000 boys in various states of India. Represent as bar graph. |
| Answer: Draw horizontal or vertical bar graph — states on one axis, number of girls on other. ✅ |
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| Q3. Given frequency distribution of India's export by a company — represent as bar graph. Compare with bar graph from Q2. |
| Answer: Draw bar graph with items on x-axis and export values on y-axis. ✅ |
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| Q4. Number of students who got various marks in different subjects — data given. Draw double bar graph. |
| Answer: For each subject, draw two bars (boys and girls) side by side. Helpful to compare. ✅ |
