# NCERT Class 10 Mathematics Chapter 14 Probability: Summary, Concepts, and Revision Notes | SwaVid

This chapter introduces the fundamental concept of Probability, a mathematical tool used to quantify the likelihood of an event occurring. It moves from...

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# Probability

## Concepts in this chapter

## The ideas this chapter keeps returning to

## Where this chapter usually trips people up

## Find the gaps before this chapter finds them for you.

## Related chapters

### Introduction to Probability and Experiment

Chapter 14 · Class 10 Mathematics

This chapter introduces the fundamental concept of Probability, a mathematical tool used to quantify the likelihood of an event occurring. It moves from intuitive ideas of chance to a formal definition, laying the groundwork for understanding uncertainty in various contexts.

Your study route

Key topics

Probability deals with quantifying the uncertainty of events. An experiment is an activity that produces a well-defined set of possible outcomes.

Example

Tossing a coin is an experiment with outcomes Head or Tail. Rolling a die is an experiment with outcomes 1, 2, 3, 4, 5, or 6.

Watch out

Confusing an experiment with a single outcome, rather than the entire process that generates outcomes.

Probability deals with quantifying the uncertainty of events. An experiment is an activity that produces a well-defined set of possible outcomes.

Tap the card for an example

Example

Tossing a coin is an experiment with outcomes Head or Tail. Rolling a die is an experiment with outcomes 1, 2, 3, 4, 5, or 6.

Why it matters

This forms the foundational understanding for all subsequent probability concepts, establishing the context for analyzing chance.

Watch out

Confusing an experiment with a single outcome, rather than the entire process that generates outcomes.

Ask at home

Ask your child to define an experiment and list all possible outcomes for simple actions like drawing a marble from a bag with different colored marbles.

Probability is a mathematical measure of the likelihood of an event happening. It is expressed as a number between 0 and 1, inclusive, where 0 indicates impossibility and 1 indicates certainty. The chapter defines key terms like experiment, outcome, event, and elementary event. It introduces the classical definition of probability as the ratio of the number of favourable outcomes to the total number of possible outcomes, assuming all outcomes are equally likely. Students learn about complementary events, where the probability of an event not happening is 1 minus the probability of it happening. The sum of probabilities of all elementary events of an experiment is always 1. Understanding these concepts is crucial for analyzing uncertain situations and making informed decisions in various real-world scenarios, from games of chance to scientific research and financial forecasting.

Chapter summary

Probability is a mathematical measure of the likelihood of an event happening. It is expressed as a number between 0 and 1, inclusive, where 0 indicates impossibility and 1 indicates certainty. The chapter defines key terms like experiment, outcome, event, and elementary event. It introduces the classical definition of probability as the ratio of the number of favourable outcomes to the total number of possible outcomes, assuming all outcomes are equally likely. Students learn about complementary events, where the probability of an event not happening is 1 minus the probability of it happening. The sum of probabilities of all elementary events of an experiment is always 1. Understanding these concepts is crucial for analyzing uncertain situations and making informed decisions in various real-world scenarios, from games of chance to scientific research and financial forecasting.

What you should learn

Keep these close

Probability quantifies the likelihood of an event occurring.

P(E) = (Number of favourable outcomes) / (Total number of possible outcomes) for equally likely outcomes.

The probability of any event E must be between 0 and 1, inclusive (0 <= P(E) <= 1).

A sure event has a probability of 1.

An impossible event has a probability of 0.

For any event E, P(E) + P(not E) = 1.

The sum of the probabilities of all elementary events in an experiment is always 1.

An elementary event is an event with only one outcome.

Carefully identify and count all possible outcomes and all favourable outcomes.

Understand the composition of a standard deck of 52 playing cards (suits, face cards, number cards).

When rolling two dice, there are 36 possible outcomes (6 x 6).

Distinguish between &#x27;at least&#x27;, &#x27;at most&#x27;, and &#x27;exactly&#x27; when defining events.

Common confusions

It is easy to think

Probability is always 1/2 for any event because it either happens or it doesn&#x27;t.

The clearer idea

This is incorrect. The 1/2 probability only applies if the two outcomes are equally likely. For example, getting a 6 on a die roll is 1/6, not 1/2, because all six faces are equally likely.

It is easy to think

If an event has not happened for a long time, it is more likely to happen next (Gambler&#x27;s Fallacy).

The clearer idea

Each trial in probability (like a coin toss or die roll) is independent. Past outcomes do not influence future outcomes for independent events. The probability remains constant for each trial.

It is easy to think

Confusing &#x27;at least&#x27; with &#x27;exactly&#x27; when defining events.

The clearer idea

These terms have distinct meanings. &#x27;At least one head&#x27; means one or more heads, while &#x27;exactly one head&#x27; means precisely one head. Always read the question carefully to identify the correct event.

It is easy to think

Incorrectly counting total outcomes, especially for multiple events (e.g., two dice or multiple coin tosses).

The clearer idea

For independent events, the total number of outcomes is found by multiplying the number of outcomes for each individual event (e.g., 6 * 6 = 36 for two dice, not 6 + 6 = 12; 2 * 2 = 4 for two coins, not 2 + 2 = 4).

Before you push ahead

Most stuck chapters trace back to one earlier idea. Check the prerequisites first, or let SwaVid adapt this chapter to the way your child learns.

Keep exploring Class 10

Source

- Define and understand basic probability terms like experiment, outcome, event, and elementary event.
- Calculate the probability of an event using the classical definition.
- Understand and apply the concept of complementary events.
- Recognize that the probability of a sure event is 1 and an impossible event is 0.
- Understand that the sum of probabilities of all elementary events of an experiment is 1.
- Define and understand basic probability terms like experiment, outcome, event, and elementary event.
- Calculate the probability of an event using the classical definition.
- Understand and apply the concept of complementary events.
- Recognize that the probability of a sure event is 1 and an impossible event is 0.
- Understand that the sum of probabilities of all elementary events of an experiment is 1.
- NCERT Class 10 Mathematics textbook: Mathematics : Chapter 14: Probability

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