An acoustical engineer is studying noise levels in center cities with day of the work week. She takes measurements each day of the week for four weeks at the same intersection and at the same time

(5 pm). The following measurements (decibels) were taken:

M Tu W Th F 66 76 66 73 70 71 74 73 67 66 70 73 68 67 65 65 75 71 71 67 Does the noise level differ from day-to-day? Use a 5% level.