---
source: ncert_exercises
topic: statistics
class_level: class_9
chapter: ch12
exercise: ex12.1
difficulty: beginner
---

Class 9 | Ch12: Statistics | Exercise 12.1

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.

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. ✅

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. ✅

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. ✅

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. ✅