To find the probability that a child has a pet or a sibling, we need to apply the principle of inclusion-exclusion.
From the Venn diagram we have:
- Probability of having a pet (P(Pet)) = 0.35
- Probability of having a sibling (P(Sibling)) = 0.43
- Probability of having both a pet and a sibling (P(Pet ∩ Sibling)) = 0.11
According to the principle of inclusion-exclusion, the probability of having a pet or a sibling (P(Pet ∪ Sibling)) is given by the formula:
\[ P(Pet ∪ Sibling) = P(Pet) + P(Sibling) - P(Pet ∩ Sibling) \]
Substituting the values, we get:
\[ P(Pet ∪ Sibling) = 0.35 + 0.43 - 0.11 \]
Calculating this:
\[ P(Pet ∪ Sibling) = 0.35 + 0.43 = 0.78 \] \[ P(Pet ∪ Sibling) = 0.78 - 0.11 = 0.67 \]
Thus, the probability that a child has a pet or a sibling is 0.67.