source: ncert_exercises
topic: statistics
class_level: class_9
chapter: ch12
exercise: ex12.2
difficulty: beginner
Class 9 | Ch12: Statistics | Exercise 12.2
Key: Frequency distribution table, histograms, frequency polygons.
Q1. A family with monthly income of ₹20000 spends on items as given. Draw a bar graph. Answer: Bar graph with expenses on x-axis and amounts on y-axis. Compare spending across categories. ✅
Q2. The distribution below gives weights of 30 students of a class. Draw a histogram. Weight(kg):40-45, 45-50, 50-55, 55-60, 60-65. No of students: 2, 3, 8, 6, 6, 3, 2. Answer: Histogram: x-axis=weight intervals (continuous), y-axis=frequency. No gaps between bars (unlike bar graph). ✅
Q3. The following table gives production yield per hectare of wheat of 100 farms. Draw histogram. Production yield (kg/ha): 50-55, 55-60, 60-65, 65-70, 70-75, 75-80. Frequency: 2, 8, 12, 24, 38, 16. Answer: Draw histogram. Bars are adjacent (continuous data). Heights = frequencies. ✅
Q4. Draw a histogram for the frequency distribution from Q3. Then draw frequency polygon. Answer: Frequency polygon: join midpoints of tops of histogram bars with straight lines. Extend to x-axis at both ends. ✅