Do workers on different shifts get different amounts of sleep per week? Some people believe that shift workers who regularly work the graveyard shift (12:00 A.M.to 8:00 A.M.) or swing shift (4:00 P.M.to 12:00 A.M.) are unable to get the same amount of sleep as day workers because of family schedules, noise, amount of daylight, and other factors. To test this theory, a researcher samples workers from day, swing, and graveyard shifts and asks each worker to keep a sleep journal for one week. The following data represent the number of hours of sleep per week per worker for the different shifts. Use the Kruskal-Wallis test to determine whether there is a significant difference in the number of hours of sleep per week for workers on these shifts. Use α =.05.

Day Shift 52 57 53 56 Swing Shift 45 48 Graveyard Shift 41 46 39 49 42 35 52 51 48 54 49 43 50 51