Home › concepts › probability basics

Probability: Basics and Sample Space Explained

Probability is the measure of likelihood that an event will occur. It ranges from 0 (impossible) to 1 (certain), expressed as a fraction, decimal, or perce

✓ 100% Free ✓ No Login Needed ✓ NCERT / CBSE Aligned ✓ Download as PDF

TL;DR: Probability is the measure of likelihood that an event will occur. It ranges from 0 (impossible) to 1 (certain), expressed as a fraction, decimal, or…

Written & reviewed by the Syllab.in Academic Team (CBSE/NCERT subject experts) · Updated Jul 23, 2026

🤖 Stuck on any question? Ask Syllab's free AI Tutor for a step-by-step explanation — instant, unlimited, no login.

Probability: Basics and Sample Space: Probability is the measure of likelihood that an event will occur. It ranges from 0 (impossible) to 1 (certain), expressed as a fraction, decimal, or perce

Probability: Basics and Sample Space Explained Simply

Probability is the measure of likelihood that an event will occur. It ranges from 0 (impossible) to 1 (certain), expressed as a fraction, decimal, or perce This is a key Maths concept for 10-12.

Frequently Asked Questions

What is the difference between probability and odds?

Probability is the ratio of favorable to total outcomes, ranging from 0 to 1. Odds express the ratio of favorable to unfavorable outcomes (e.g., 2:3 odds). A probability of 0.4 equals odds of 2:3.

Can you multiply probabilities when events are not independent?

No, for independent events only. For dependent events, use conditional probability: P(A and B) = P(A) × P(B given A). Drawing two cards without replacement requires using conditional probability.

Why is a 95% accurate test sometimes unreliable?

If a disease is very rare (e.g., 1 in 1000), even a 95% accurate test will have many false positives. Among 1000 people, 1 has the disease (99% chance of positive). 999 don't have it, but 5% test positive (50 false positives). So a positive test means only about 2% chance of actually having it (1 in 51).

Related Maths Concepts

  • Arithmetic Progressions and Series Explained
  • Statistics: Mean, Median, Mode, and Measures of Spread Explained
  • Surface Area and Volume of Solids Explained

Browse all concepts →

Explore:

  • Syllabus
  • Practice
  • Mock Tests
  • NCERT Solutions
  • Coding
  • GK Quiz
  • Career Predictor
  • AI Tutor
  • Live Quiz
  • Doubt Solver
  • Microlearning
  • Free Alternatives
  • Kids Zone
  • Study Room
  • Calculators
  • Worksheets

Syllab.in — Free learning for Indian students, Class 1–12