Simple Event

Probability denotes how likely an event will happen. In probability, simple, compound and complementary events are different types of probabilities.

Definition

If an event $E$ has only one sample point of a sample space, it is called a simple (or elementary) event. In a sample space containing $n$distinct elements, there are exactly $n$ simple events.

For example in the experiment of tossing two coins, a sample space is $S=\{HH,HT,TH,TT\}$

There are four simple events corresponding to this sample space. These are

$E_{1}=\{HH\}$ , $E_{2}=\{HT\}$, $E_{3}=\{TH\}$ , $E_{4}=\{TT\}$

Probability of an event occurring = No. of favorable outcomes / total no. of outcomes

Example

The probability of getting a $4$ when a die is tossed

$S=\{1,2,3,4,5,6\}$

If $E$ be the event of getting a $4$ when a die is tossed. $E=\{4\}$

$P(E)={\frac {1}{6}}$

In the case of a simple event, the numerator (number of favorable outcomes) will be 1.