At Westonci.ca, we make it easy to get the answers you need from a community of informed and experienced contributors. Ask your questions and receive detailed answers from professionals with extensive experience in various fields. Explore comprehensive solutions to your questions from knowledgeable professionals across various fields on our platform.

A survey asked students whether they have any siblings and pets. The survey data are shown in the relative frequency table below:

\begin{tabular}{|c|c|c|c|}
\hline & Siblings & No siblings & Total \\
\hline Pets & 0.3 & 0.15 & 0.45 \\
\hline No pets & 0.45 & 0.1 & 0.55 \\
\hline Total & 0.75 & 0.25 & 1.0 \\
\hline
\end{tabular}

Given that a student has a sibling, what is the likelihood that he or she does not have a pet?

A. About [tex]$82\%$[/tex]
B. [tex]$45\%$[/tex]
C. [tex]$40\%$[/tex]
D. [tex]$60\%$[/tex]

Sagot :

To determine the likelihood that a student who has a sibling does not have a pet, we can perform the following steps:

1. Identify the given probabilities from the table:
- Probability that a student has a sibling, [tex]\( P(\text{Sibling}) \)[/tex]: 0.75
- Probability that a student has both a sibling and no pets, [tex]\( P(\text{No Pets and Sibling}) \)[/tex]: 0.45

2. Understand what is required:
- We need to find the conditional probability [tex]\( P(\text{No Pets} \mid \text{Sibling}) \)[/tex], which reads as "the probability of no pets given that the student has a sibling."

3. Apply the formula for conditional probability:
[tex]\[ P(\text{No Pets} \mid \text{Sibling}) = \frac{P(\text{No Pets and Sibling})}{P(\text{Sibling})} \][/tex]

4. Substitute the values:
[tex]\[ P(\text{No Pets} \mid \text{Sibling}) = \frac{0.45}{0.75} \][/tex]

5. Calculate the likelihood:
- Simplify the fraction:
[tex]\[ \frac{0.45}{0.75} = 0.6 \][/tex]

6. Convert the likelihood to a percentage:
[tex]\[ 0.6 \times 100 = 60\% \][/tex]

7. Round to the nearest whole number, if needed. In this case, 60 is already a whole number.

Therefore, the likelihood that a student who has a sibling does not have a pet is [tex]\( \boxed{60\%} \)[/tex].

Given the answer choices:
A. About [tex]\( 82 \% \)[/tex]
B. [tex]\( 45 \% \)[/tex]
C. [tex]\( 40 \% \)[/tex]
D. [tex]\( 60 \% \)[/tex]

The correct answer is [tex]\( \boxed{60 \%} \)[/tex].