Data Handling (NCERT Ch. 5)

• Organise data using frequency distribution tables and grouped data (class intervals).
• Represent data using histograms and pie charts.
• Understand basic probability with everyday examples.

1. Grouped data is organised into class intervals (e.g., 0-10, 10-20) with a frequency for each interval.
2. A histogram is a bar graph for grouped/continuous data with no gaps between bars.
3. A pie chart represents data as slices of a circle, each slice proportional to its share of the whole (360°total).
4. Central angle for a pie slice = (value/total) x 360°.
5. Probability = (favourable outcomes) / (total possible outcomes).

In a pie chart, if a category has 90 out of 360 total students, find its central angle.

Angle = (90/360) x 360 = 90°

• Leaving gaps between bars in a histogram (unlike a regular bar graph, histograms should be continuous for grouped data).
• Forgetting that pie chart angles must always sum to 360°.
• Confusing class interval boundaries — the upper limit of one interval usually excludes overlap with the next (e.g. 0-10, 10-20 — 10 belongs to 10-20 by convention).

• If a pie chart shows a category with a 60° angle, what fraction of the total does it represent?
• What is a histogram used for?

Open the Practice tab for graded questions on Data Handling (NCERT Ch. 5).