An experiment was done to look at whether different relaxation techniques could predict sleep quality better than nothing. a sample of 400 participants were randomly allocated to one of four groups: massage, hot bath, reading or nothing. for one month each participant received the same relaxation technique for 30 minutes before going to bed each night. a special device was attached to the participant’s wrist that recorded their quality of sleep, providing them with a score out of 100. the outcome was the average quality of sleep score over the course of the month. which test could we use to analyse these data? a. regression or anova b. regression only c. anova only d. chi-square