Sophie pays m dollars to rent a car for the weekend. On the drive home, she buys $25 worth of gasoline. Her friend Melody pays for one-half the cost of the car rental only. Choose an expression you could use to determine how much Sophie spent. A. m + 25
B. m + 25 –1/2
C. 1/2(m + 25)
D. 1/2m + 25

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?