Question

a survey asked students whether they have any siblings and pets. the survey data are shown in the relative - frequency table.

	siblings	no siblings	total
no pets	0.45	0.1	0.55
total	0.75	0.25	1.0

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

a. about 33%
b. 60%
c. 75%
d. 15%

Explanation:

Step1: Identify relevant frequencies

We want the probability of having a pet given no - siblings. The frequency of students with no siblings and pets is 0.15, and the total frequency of students with no siblings is 0.25.

Step2: Use conditional - probability formula

The formula for conditional probability $P(A|B)=\frac{P(A\cap B)}{P(B)}$. Here, $A$ is having a pet and $B$ is having no siblings. So the probability $P=\frac{0.15}{0.25}$.

Step3: Calculate the probability

$\frac{0.15}{0.25}=0.6$.

Step4: Convert to percentage

$0.6\times100\% = 60\%$.

Answer:

B. 60%