Class 8 Chapter 18: Probability

# Class 8 Chapter 18: Probability

Important Concepts and Formulas

1.      Probability is a branch of mathematics that deals with the chance of occurrence of an event.

2.      There are three different situations that we come across in our daily life. They may be
·        sure to happen
·        impossible to happen
·        having some chances of happening.

3.      A random experiment is a process whose outcome (result) cannot be predicted in advance.

4.      Outcomes of an experiment are equally likely if each has the same chance of occurring.

5.      The collection of outcomes is called an event.

6.      The sample space of an event is the list of all possible outcomes of an event.

7.      The probability of an event E is denoted by P(E) and defined as follows:

8.      Symbolically, for finite number of possible outcomes, Probability of an event E, P(E) = n(E)/n(S), where, n(E) is the number of favorable outcomes and n(S) is the number of possible outcomes.

9.      Probability of an event lies between 0 and 1, inclusive of both.

10. The probability of a sure event is always 1 and the probability of an impossible event is always 0.