A survey found the distribution of some families by size as follows.

\begin{tabular}{|l|c|c|c|c|c|c|c|}
\hline Family Size & 2 & 3 & 4 & 5 & 6 & 7 & 8 \\
\hline Frequency & 87 & 50 & 61 & 31 & 16 & 3 & 2 \\
\hline
\end{tabular}

Find the probability of a family having 4 people.

[tex]\[ P(4) = \,? \][/tex]



Answer :

To find the probability of a family having 4 members based on the given survey data, follow these steps:

1. Identify the family sizes and their corresponding frequencies:
- Family sizes: 2, 3, 4, 5, 6, 7, 8
- Frequencies: 87, 50, 61, 31, 16, 3, 2

2. Calculate the total number of families surveyed:
- Add up all the frequencies to get the total number of families.
[tex]\[ \text{Total number of families} = 87 + 50 + 61 + 31 + 16 + 3 + 2 = 250 \][/tex]

3. Find the frequency of families with 4 members:
- According to the given data, the frequency of families with 4 members is 61.

4. Calculate the probability of a family having 4 members:
- The probability [tex]\( P(4) \)[/tex] is given by the ratio of the frequency of families with 4 members to the total number of families.
[tex]\[ P(4) = \frac{\text{Frequency of families with 4 members}}{\text{Total number of families}} \][/tex]
Substituting the numbers:
[tex]\[ P(4) = \frac{61}{250} \][/tex]

5. Simplified probability:
- Divide 61 by 250 to get the probability in decimal form.
[tex]\[ P(4) = 0.244 \][/tex]

Therefore, the probability of picking a family with 4 members from the surveyed families is:
[tex]\[ P(4) = 0.244 \][/tex]