---
source: ncert
topic: statistics
class_level: class_7
chapter: ch3
difficulty: beginner
---

Class 7 | Ch3: Data Handling
Mean=Sum/n. Mean of first n natural numbers=(n+1)/2.
Median: arrange in order. Odd: middle term. Even: average of two middle terms.
Mode: most frequent. Range=Max-Min.
Double bar graph: compares two datasets side by side.
Probability: P(event)=favourable/total. Between 0 and 1.
Example: 4,7,2,9,4,8,4,6. Mean=44/8=5.5. Arranged:2,4,4,4,6,7,8,9. Median=(4+6)/2=5. Mode=4.
P(even on die)=3/6=1/2 (even numbers: 2,4,6).
Always arrange data BEFORE median. Probability never exceeds 1.