Homework?
In general, scatter charts let you see if X and Y seem to be related.
For example: for a math class let X be number of hours spend doing homework
for each student and let Y be each student's exam mark (convert A to 80, B
to 75, etc if needed).
Can a line approximate the data? A rising line shows the more hours spent on
homework the better the grade. If no line approximates the data then there
is no relationship.
Want more? Time to read a statistics book
best wishes