The table shows the result of a restaurant survey.
\begin{tabular}{|c|c|c|c|}
\hline Meals & Service good & Service poor & Total \\
\hline Lunch & 22 & 50 & 72 \\
Dinner & 38 & 23 & 61 \\
Total & 60 & 73 & 133 \\
\hline
\end{tabular}

Find the probability that the service was good, given that the meal was lunch.

The probability that the service was good, given that the meal was lunch, is [tex]$\square$[/tex]
(Type an integer or a simplified fraction.)



Answer :

To find the probability that the service was good given that the meal was lunch, we need to use the concept of conditional probability.

The probability of an event [tex]\( A \)[/tex] occurring given that event [tex]\( B \)[/tex] has occurred can be calculated using the formula:
[tex]\[ P(A|B) = \frac{P(A \cap B)}{P(B)} \][/tex]

In this problem, we want to find the probability that the service was good (event [tex]\( A \)[/tex]) given that the meal was lunch (event [tex]\( B \)[/tex]).

From the table, we observe the following:
- The number of times the service was good during lunch ([tex]\( A \cap B \)[/tex]) = 22.
- The total number of lunch meals ([tex]\( B \)[/tex]) = 72.

So, we calculate the probability as:
[tex]\[ P(\text{Service good | Lunch}) = \frac{\text{Number of times service was good during lunch}}{\text{Total number of lunch meals}} = \frac{22}{72} \][/tex]

Simplifying the fraction:
[tex]\[ \frac{22}{72} = \frac{11}{36} \][/tex]

Thus, the probability that the service was good given that the meal was lunch is:
[tex]\[ \boxed{\frac{11}{36}} \][/tex]