Dowsing
A water dowser claims to be able to sense the presence of water using a forked stick. Suppose we wish to set up an experiment to test his ability. We get 20 identical containers, fill some with water, and ask the dowser to tell which ones are full and which empty.
a) How will we randomize this procedure?
b) The dowser correctly identifies the contents of 12 out of 20 containers. Do you think this level of success is statistically significant? Explain.
c) How many correct identifications (out of 20) would the dowser have to make to convince you that the forked-stick trick works? Explain.