Statistics and data science in general is huge and growing area. You've all heard the buzz words of big data, AI, machine learning and so on.
At out first meeting some students suggested surveying youth at a local center to collect data on video game use. To expand on this, I would suggest something along the following lines
Collect data not just on video games, but other kinds of leisure, homework, and so on.
Survey students in different grades 7, 8 and 9.
To get enough data to do some meaningful statistics you would need to survey around 100 students from each grade.
Learn some ways measuring variation in data and well as how to visually present the results. . You probably know about mean/average, median and mode. Learn about the normal distribution (aka bell curve), standard deviation, and percentiles.
Important! Think about what you want to measure and the mathematics before you make the survey. This ensures they questions are asked in a way to obtain the data you need.