Can a straight line be drawn through any two points

Given the parent function of [tex]f(x)=x^4[/tex], what change will occur when the function is changed to [tex]f(\frac{1}{2} x)[/tex]?

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?

Me. i can't figure out this question. give an explanation too. .