Final answer:
In this study, the population refers to all families with children at Knoll Academy, the sample refers to the 3 families randomly surveyed, the variable refers to the amount of money spent on school uniforms, and the data refers to the specific amounts of money spent by the 3 families.
Step-by-step explanation:
The key terms in this study are:
Population: all families with children at Knoll Academy
Sample: the randomly surveyed 3 families
Variable: the amount of money spent on school uniforms
Data: the specific amounts of money spent by the 3 families, which are $65, $75, and $95