In a preliminary study to determine whether the installation of a camera designed to catch cars that go through red lights affects the number of violators, the number of red-light runners was recorded for each day of the week before and after the camera was installed. These data are listed here. Can we infer that the camera reduces the number of red-light runners?
Day Sunday Monday Tuesday Wednesday Thursday Friday Saturday
Before 7 21 27 18 20 24 16
After 8 18 24 19 16 19 16