What is the slope of -4,5 & 1,-7.5

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?

What is the volume of this container?

The complement of an angle is one-sixth the measure of the supplement of the angle. what is the measure of the complement angle?