Class 7 · Chapter 3

Data Handling

Mean, median, mode; bar graphs; probability of an event.

Read the full chapter
Tip: open the NCERT PDF for the original chapter text alongside the notes here.
Detailed theory
Mean = sum ÷ count. Median = middle value (after sorting). Mode = most frequent value. All three describe a 'centre' but differ in sensitivity to outliers.
Key concepts & formulas
01
Mean =xn= \dfrac{\sum x}{n}.
02
Median is the middle value of sorted data.
03
Mode is the most frequent value.
04
Range == max - min.
05
Probability of event E=favourable outcomestotal outcomesE = \dfrac{\text{favourable outcomes}}{\text{total outcomes}}.
Gyaan Maths — CBSE Class 6-10, built for board-toppers.
v1.1 · Feb 2026