Find [tex]$P(C \mid Y)$[/tex] from the information in the table.

\begin{tabular}{|c|c|c|c|c|}
\hline & [tex]$X$[/tex] & [tex]$Y$[/tex] & [tex]$Z$[/tex] & Total \\
\hline A & 32 & 10 & 28 & 70 \\
\hline B & 6 & 5 & 25 & 36 \\
\hline C & 18 & 15 & 7 & 40 \\
\hline Total & 56 & 30 & 60 & 146 \\
\hline
\end{tabular}

To the nearest tenth, what is the value of [tex]$P(C \mid Y)$[/tex]?

A. 0.4
B. 0.5
C. 0.7
D. 0.8



Answer :

To find [tex]\( P(C \mid Y) \)[/tex], which is the probability of event [tex]\( C \)[/tex] given event [tex]\( Y \)[/tex], we need to follow these steps:

1. Identify the total number of occurrences of event [tex]\( Y \)[/tex].
2. Identify the number of occurrences where both events [tex]\( C \)[/tex] and [tex]\( Y \)[/tex] happen.
3. Use the conditional probability formula:
[tex]\[ P(C \mid Y) = \frac{\text{Number of occurrences of both } C \text{ and } Y}{\text{Total number of occurrences of } Y} \][/tex]

Looking at the given table, we extract the necessary information:

- The total number of occurrences of [tex]\( Y \)[/tex] is found in the "Total" column under [tex]\( Y \)[/tex]. This is:
[tex]\[ \text{Total}_{Y} = 30 \][/tex]

- The number of occurrences of both [tex]\( C \)[/tex] and [tex]\( Y \)[/tex] is found at the intersection of row [tex]\( C \)[/tex] and column [tex]\( Y \)[/tex]. This is:
[tex]\[ \text{Total}_{C \cap Y} = 15 \][/tex]

Using these values in the conditional probability formula, we calculate:
[tex]\[ P(C \mid Y) = \frac{15}{30} = \frac{1}{2} = 0.5 \][/tex]

To the nearest tenth, the value of [tex]\( P(C \mid Y) \)[/tex] is:
[tex]\[ 0.5 \][/tex]

So, the closest value to the answer is:
[tex]\[ 0.5 \][/tex]