# Class 9 Maths Revision Notes for Probability of Chapter 15

## Class 9 Maths Revision Notes for Probability of Chapter 15 - Free PDF Download

**CBSE Class 09 Mathematics Revison Notes Chapter 15 PROBABILITY**

**Probability – An Experimental Approach**

- Experiment - A procedure which produces some well defined possible outcomes..
- Random experiment - An experiment which when performed produces one of the several possible outcomes called a random experiment.
- Trial - When we perform an experiment it is called a trial of the experiment.
- Event - The set of outcomes of an experiment to which probability is assigned.It is usually denoted by capital letter of English alphabets like A, B, E etc.
- A collection of two or more possible outcomes (elementary events) of an experiment called a compound event.
- An event is said to be happen in trial if any one of the elementary events (or outcomes) satisfying its conditions is an outcome.
- The empirical (or experimental) probability P(E) of an event E is given by $P(E)=\frac{Number\phantom{\rule{thickmathspace}{0ex}}of\phantom{\rule{thickmathspace}{0ex}}trials\phantom{\rule{thickmathspace}{0ex}}in\phantom{\rule{thickmathspace}{0ex}}which\phantom{\rule{thickmathspace}{0ex}}E\phantom{\rule{thickmathspace}{0ex}}has\phantom{\rule{thinmathspace}{0ex}}happend}{Total\phantom{\rule{thinmathspace}{0ex}}no.\phantom{\rule{thinmathspace}{0ex}}of\phantom{\rule{thickmathspace}{0ex}}trial}$
- The probability of an event lies between 0 and 1 (0 and 1 are included)
- Impossible event: Event which never happen.
- Certain event - event which definitely happen.