The nursing supervisor in a local health department wished to study the influence of time of day on length of home visits by the nursing staff. It was thought that individual differences among nurses might be large, so the nurse was used as a blocking factor. The nursing supervisor collected the following data:

Length of Home Visit by Time of Day Nurse Early Morning Late Morning Early Afternoon Late Afternoon A 27 28 30 23 B 31 30 27 20 C 35 38 34 30 D 20 18 20 14 Do these data provide sufficient evidence to indicate a difference in length of home visit among the different times of day? Let a ¼ :05.