Select the correct answer.

The probability that Roger wins a tennis tournament (event [tex]$A$[/tex]) is 0.45, and the probability that Stephan wins the tournament (event [tex]$B$[/tex]) is 0.40. The probability of Roger winning the tournament, given that Stephan wins, is 0. The probability of Stephan winning the tournament, given that Roger wins, is 0. Given this information, which statement is true?

A. Events [tex]$A$[/tex] and [tex]$B$[/tex] are not independent because [tex]$P(A \mid B)=P(A)$[/tex].
B. Events [tex]$A$[/tex] and [tex]$B$[/tex] are independent because [tex]$P(A \mid B) \neq P(A)$[/tex].
C. Events [tex]$A$[/tex] and [tex]$B$[/tex] are independent because [tex]$P(A \mid B)=P(A)$[/tex].
D. Events [tex]$A$[/tex] and [tex]$B$[/tex] are not independent because [tex]$P(A \mid B) \neq P(A)$[/tex].



Answer :

To determine whether events \( A \) and \( B \) are independent, we need to check if the probability of \( A \) given \( B \) is equal to the probability of \( A \), and if the probability of \( B \) given \( A \) is equal to the probability of \( B \).

Step-by-Step Solution:

1. Given Information:
- \( P(A) = 0.45 \): The probability that Roger wins.
- \( P(B) = 0.40 \): The probability that Stephan wins.
- \( P(A \mid B) = 0.00 \): The probability that Roger wins given that Stephan wins.
- \( P(B \mid A) = 0.00 \): The probability that Stephan wins given that Roger wins.

2. Independence Criteria:
Events \( A \) and \( B \) are independent if:
[tex]\[ P(A \mid B) = P(A) \quad \text{and} \quad P(B \mid A) = P(B) \][/tex]

3. Check the Given Probabilities:
- \( P(A \mid B) = 0.00 \) and \( P(A) = 0.45 \):
Since \( P(A \mid B) \neq P(A) \), the first condition for independence is not met.

- \( P(B \mid A) = 0.00 \) and \( P(B) = 0.40 \):
Since \( P(B \mid A) \neq P(B) \), the second condition for independence is also not met.

4. Conclusion:
Since neither condition for independence is satisfied, events \( A \) and \( B \) are not independent.

Therefore, the correct statement is:
D. Events \( A \) and \( B \) are not independent because \( P(A \mid B) \neq P(A) \).

Hence, the answer is D.

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