Pls i need this answered correctly,

Use the function f(x) is graphed below. the graph of the function to find, f(6). -2 -1 1 2

What is the average rate of change for this function for the interval from x=2 to x=4 ?

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?