400
Beth is setting up an experiment to determine if children score higher on tests if they listen to music while studying. She conducts a controlled experiment in which 100 of her 7th grade classmates take tests after studying with and without music. What is the big problem?
Beth's sample of !00 7th grade students does not represent the group she identified in her question. The sample must be representative of the population. She needs to change her question to 7th grade students or she needs to test children of all ages.