• You wish to determine if children's mental health has changed since the return to school. A very large scale study in 2021 during school lockdown found that 10 year old children had an average score on a test of mental health of 25.6 (SD = 8.4). You test 25 children now and find that their average score is 26.8 (SD = 7.8).

Is this a study or an experiment? (why?)

What is the appropriate test to use? WHY?