Plz help me on this geometry assignment

Given the graph below state whether or not the relation is a function, and give the domain and range.

Asap 25 pts + brainlest to right/best answer

1. there are 25 students who started computer programming in elementary school and 25 students who started computer programming in middle school. the first group had a mean final project grade of 95% and the second group had a mean final project grade of 92%. the line plot shows the differences after 10 rerandomizations. determine whether the difference in the means of the two groups is significant based on the line plot. explain your answer.