\begin{tabular}{|c|c|c|c|c|}
\hline & [tex]$X$[/tex] & [tex]$Y$[/tex] & [tex]$Z$[/tex] & Total \\
\hline A & 10 & 80 & 61 & 151 \\
\hline B & 110 & 44 & 126 & 280 \\
\hline C & 60 & 59 & 110 & 229 \\
\hline Total & 180 & 183 & 297 & 660 \\
\hline
\end{tabular}

Which statement is true about whether [tex]$Z$[/tex] and [tex]$B$[/tex] are independent events?

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



Answer :

To determine whether [tex]\( Z \)[/tex] and [tex]\( B \)[/tex] are independent events, we need to compare the conditional probability [tex]\( P(Z \mid B) \)[/tex] with the probability [tex]\( P(Z) \)[/tex].

First, we calculate the probability [tex]\( P(Z) \)[/tex]:

[tex]\[ P(Z) = \frac{\text{Total count for } Z}{\text{Total count}} = \frac{297}{660} \][/tex]

Next, we calculate the probability [tex]\( P(B) \)[/tex]:

[tex]\[ P(B) = \frac{\text{Total count for } B}{\text{Total count}} = \frac{280}{660} \][/tex]

Then, we determine the conditional probability [tex]\( P(Z \mid B) \)[/tex]:

[tex]\[ P(Z \mid B) = \frac{\text{Count for both } B \text{ and } Z}{\text{Total count for } B} = \frac{126}{280} \][/tex]

To confirm whether [tex]\( Z \)[/tex] and [tex]\( B \)[/tex] are independent events, we check if [tex]\( P(Z \mid B) = P(Z) \)[/tex].

We start by verifying if the calculated values for [tex]\( P(Z) \)[/tex] and [tex]\( P(Z \mid B) \)[/tex] are equal. According to the given information, these values match:

[tex]\[ P(Z) = \frac{297}{660} \approx 0.45 \][/tex]
[tex]\[ P(Z \mid B) = \frac{126}{280} \approx 0.45 \][/tex]

Since [tex]\( P(Z \mid B) = P(Z) \)[/tex], we conclude that [tex]\( Z \)[/tex] and [tex]\( B \)[/tex] are independent events.

Therefore, the correct statement is:

- [tex]\( Z \)[/tex] and [tex]\( B \)[/tex] are independent events because [tex]\( P(Z \mid B) = P(Z) \)[/tex].

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