Select the correct answer.

Two events, [tex]E_1[/tex] and [tex]E_2[/tex], are defined for a random experiment. Which equation represents the condition that the events are nonexclusive?

A. [tex]P\left(E_1 \cup E_2\right)=1[/tex]
B. [tex]P\left(E_1 \cup E_2\right) \neq 1[/tex]
C. [tex]P\left(E_1 \cap E_2\right) \neq 0[/tex]
D. [tex]P\left(E_1 \cap E_2\right)=0[/tex]



Answer :

To determine the condition for two events [tex]\(E_1\)[/tex] and [tex]\(E_2\)[/tex] to be nonexclusive, we first need to understand what nonexclusive events are.

Nonexclusive events are those that can occur simultaneously, meaning there is a possibility that both events can happen at the same time. In probability terms, this means that the intersection of the two events [tex]\(E_1\)[/tex] and [tex]\(E_2\)[/tex] is not empty, i.e., there exists some outcome in the sample space that belongs to both events.

Mathematically, this condition can be represented as:
[tex]\[ P(E_1 \cap E_2) \neq 0 \][/tex]

Let's evaluate each given option to see which one matches this condition:

A. [tex]\( P(E_1 \cup E_2) = 1 \)[/tex]
- This condition states that the union of [tex]\(E_1\)[/tex] and [tex]\(E_2\)[/tex] covers the entire sample space, meaning at least one of these events always happens. However, this does not specifically address whether [tex]\(E_1\)[/tex] and [tex]\(E_2\)[/tex] can occur together or not.

B. [tex]\( P(E_1 \cup E_2) \neq 1 \)[/tex]
- This condition states that the union of [tex]\(E_1\)[/tex] and [tex]\(E_2\)[/tex] does not cover the entire sample space. Again, this condition does not provide information about the simultaneous occurrence of [tex]\(E_1\)[/tex] and [tex]\(E_2\)[/tex].

C. [tex]\( P(E_1 \cap E_2) \neq 0 \)[/tex]
- This condition states that the intersection of [tex]\(E_1\)[/tex] and [tex]\(E_2\)[/tex] is not empty, meaning there is a nonzero probability that both [tex]\(E_1\)[/tex] and [tex]\(E_2\)[/tex] occur together. This is the condition we are looking for to define nonexclusive events.

D. [tex]\( P(E_1 \cap E_2) = 0 \)[/tex]
- This condition states that the intersection of [tex]\(E_1\)[/tex] and [tex]\(E_2\)[/tex] is empty, meaning there is no possibility of both events occurring simultaneously. This describes exclusive (or mutually exclusive) events, which is the opposite of what we need.

Therefore, the correct answer is:
C. [tex]\( P(E_1 \cap E_2) \neq 0 \)[/tex]