Answer:
1.
The explanatory variable is whether or not the student received tutoring. The response variable is the student's Geometry test score.
2.
The situation described is an observational study. In an observational study, the researcher does not control the variables. In this case, the researcher did not control whether or not the students received tutoring.
3.
Yes, I think the fact that the students were not required to do tutoring and signed up for it voluntarily may impact the scores. Students who are motivated enough to sign up for tutoring may be more likely to be high achievers in the first place.
4.
Some other possible variables that may explain why the Geometry test scores are higher for those who did tutoring than for those who did not do tutoring include:
- The amount of time spent tutoring
- The quality of the tutoring
- The student's prior knowledge of Geometry
- The student's motivation
- The student's study habits
- The student's learning style
5.
Based on this study, we cannot conclude that tutoring caused the students' Geometry test scores to increase. The study is observational, and there are many other possible explanations for the difference in test scores.
6.
To design an experiment that would allow us to determine if tutoring causes an increase in Geometry test scores, we would need to do the following:
- Randomly assign students to either a tutoring group or a control group.
- Provide the tutoring group with tutoring for a specific period of time.
- Give both groups the same Geometry test at the end of the study.
- Compare the test scores of the two groups.
If the tutoring group scores significantly higher than the control group, then we can conclude that tutoring caused the increase in test scores.