Task 3: Students (and lecturers for that matter) love their mobile phones, which is rather worrying given some recent controversy about links between mobile phone use and brain tumours. The basic idea is that mobile phones emit microwaves, and so holding one next to your brain for large parts of the day is a bit like sticking your brain in a microwave oven and selecting the 'cook until well done' button. If we wanted to test this experi- mentally, we could get six groups of people and strap a mobile phone to their heads (that they can't remove). Then, by remote control, we turn the phones on for a certain amount of time each day. After 6 months, we measure the size of any tumour (in mm) close to the site of the phone antenna (just behind the ear). The six groups experienced 0, 1, 2, 3, 4 or 5 hours per day of phone microwaves for 6 months. The data are in Tumour.sav. (From Field & Hole, 2003, so there is a very detailed answer in there).