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 her ability. We get 20 identical containers, fill half with water, and ask the dowser to tell which ones are full and which are empty. Complete parts a through c below.

a.) How will we randomize this procedure?

A.) Locate the containers in two areas. One area is filled with water and one area is empty.

B.) Fill the first 10 containers with water.

C.) Ask the dowser at different times on different days to identify one container at a time.

D.) Arrange the 20 containers in 20 separate locations. Use a random number generator to identify the 10 containers that should be filled with water.

b.) The dowser correctly identifies the contents of 12 out of 20 containers. Do you think this level of success is statistically significant?

A.) Yes

B.) No

c. How many correct identifications (out of 20) would the dowser have to make to convince you, using statistics, that the forked stick trick works? Assume that statistical significance would mean a success rate of 90% or higher.

A.) 18

B.) 12

C.) 20

D.) 10