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 one of these relaxation techniques 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?