Which relation is not a function?

Researchers were interested in whether relaxation training decreases the number of headaches a person experiences. they randomly assigned 20 participants to a control group or a relaxation training group and noted the change in number of headaches each group reported from the week before training to the week after training. which statistical analysis should be performed to answer the researchers' question?

Miguel’s teacher asks him to color 4/8 of his grid. he must use 3 colors: red, blue, and green. there must be more green sections than red sections. how can miguel color all the sections of his grid to follow all the rules

What percent of the circle below is shaded?