Then answer for thus is cheese
Answer:
<u>A. Higher than her sister's score</u>
Explanation:
Social and economic stress leads a child to less IQ level than a privileged child. It's because they have low opportunities to learn and grow, they struggle from the childhood and may have little or no access to education. Meanwhile a child in privileged family doesn't face difficulties and they get education from much advanced institutes.
Sample bias. It is a bias in that happens when a sample is collected in such a way that some members of the intended population are less likely to be included than others.