7. Shock! Horror! NewsflashJune 13, 2013
A number of women develop breast cancer who worked in the same office. This happened in ABC offices in Australia in 2006.
A link was assumed but after exhaustive tests no environmental cause was found.
Tragically, independent events can cluster. One episode of Numb3rs explained this possibility very well. If you fire a machine gun at a barn wall and draw a circle around a group of bullet holes later that is a cluster. But don’t try this at home, mathspiggies.
There is a great explanation of clustering here. Some Aussie road signs show clusters of IDIOTS!