Hey BoCat, dimensional analysis is something you did back in intro to chem. It's basically a game of cancelling the units. Example question is you are directed to administer 2mg of Morphine. You have a 10mg/ml syringe. How many ml do you inject?
The analysis is that you want an answer in ml so that unit must be on top and cancel the others - like back in math class with fractions (1/2 x 2/5 = 1/5 because the 2's cancel out)
SO.... 2 mg X 1ml/10mg = 0.2 ml
the mg behind the 2 is cancelled by the mg by the 10 leaving you with ml...the unit you want in your answer
http://www.alysion.org/dimensional/analysis.htm