Union of Events/Examples

Examples of Unions of Events

Both Prime and Even

Consider the experiment $\EE$ such that $2$ (positive) integers are drawn at random from a table of random numbers.

Let $A$ be the event that at least $1$ of these integers is prime.

Let $B$ be the event that at least $1$ of these integers is even.

Then their union $A \cup B$ means:

either of the $2$ integers is even or either of the $2$ integers is prime.

Defective Devices

Consider the experiment $\EE$ such that $3$ devices are checked as to whether they are operational.

Let $A$ be the event that at least $1$ of these $3$ devices is defective.

Let $B$ be the event that all $3$ devices are sound.

Then their union $A \cup B$ is a certainty.