Subject: Which uses more water, a shower or a bath?

In my experiment, I controlled variables by using the same bathtub/shower for 3 
experiments, and controlled the time, allowing 5 minutes for each bath and 
shower tested.  How would I make a graph showing that in all 3 tests, the 
results were the same; 13.5 cm of water is used for a shower and 16.0 cm is 
used for a bath.  Should I also conduct the same tests without restricting the 
time to 5 minutes, to show that the amount of water used depends on the user 
(i.e., an adult may take more time to take a bath or shower than a child)?  
Thank you.  

Re: Which uses more water, a shower or a bath?