## Answer :

1.

**The conditional probability formula is [tex]$P(X \mid Y)=\frac{P(X \cap \cap}{P(\cap)}$[/tex]**:

This statement appears to have a formatting issue that makes it hard to interpret correctly. If the intended formula is [tex]$P(X \mid Y) = \frac{P(X \cap Y)}{P(Y)}$[/tex], then it's correct. However, given the provided notation issue in the statement, it's better to mark this as incorrect.

2.

**The conditional probabilities [tex]$P(D \mid N)$[/tex] and [tex]$P(N \mid D)$[/tex] are equal for any events [tex]$D$[/tex] and [tex]$N$[/tex]**:

This statement is incorrect. Conditional probabilities [tex]$P(D \mid N)$[/tex] and [tex]$P(N \mid D)$[/tex] are generally not equal. For example, if [tex]$D$[/tex] and [tex]$N$[/tex] are not independent events, then [tex]$P(D \mid N)$[/tex] can be very different from [tex]$P(N \mid D)$[/tex].

3.

**The notation [tex]$P(R \mid S)$[/tex] indicates the probability of event [tex]$R$[/tex], given that event [tex]$S$[/tex] has already occurred**:

This statement is correct. The notation [tex]$P(R \mid S)$[/tex] correctly describes the conditional probability of [tex]$R$[/tex] given that [tex]$S$[/tex] has occurred.

4.

**Conditional probability applies only to independent events**:

This statement is incorrect. Conditional probability is actually more relevant when dealing with dependent events. If two events are independent, then [tex]$P(R \mid S) = P(R)$[/tex], which trivializes the concept of conditional probability. Conditional probability helps describe the relationship between dependent events.

5.

**Conditional probabilities can be calculated using a Venn diagram**:

This statement is correct. Venn diagrams can be used as a visual tool to help understand and calculate conditional probabilities by illustrating the overlap between events.

Therefore, the correct statements are:

- The notation [tex]$P(R \mid S)$[/tex] indicates the probability of event [tex]$R$[/tex], given that event [tex]$S$[/tex] has already occurred.

- Conditional probabilities can be calculated using a Venn diagram.

These correspond to statements 3 and 5.