A parapsychologist asks nine participants who each claim psychic powers to use these to induce carelessness in customers visiting a crockery shop. Participants are to induce an increase in the...

A parapsychologist asks nine participants who each claim psychic powers to use these to induce carelessness in customers visiting a crockery shop. Participants are to induce an increase in the breakage rate due to customer accidents while the customers examine stock. Each participant is asked to ‘will’ customers to break items on a specified, but different, morning (the test day). The numbers of breakages per 500 customers entering the shop on each test day is compared with the number of breakages per 500 customers entering the shop on the same day of the previous week (the control day), when no such attempt to produce breakages had been made. The results (numbers of items broken per 500 customers) for the nine participants are shown in the table below. Analyse these results using a distribution-free method to determine whether or not they provide acceptable evidence that a paranormal phenomenon occurred.