Subject: What is the relationship between the length of a beam and the am't it bends

We are doing a graphical analysis to determine how much a beam (yard 
stick) bends when there is a weight on the end and we vary the length of 
the beam.  Some groups are getting it to be h=kl^2 and others h=kl^3 where 
h is the amount of bend, l is the length of the beam and k is a constant. 
Do you know the relationship?  Thanks

Re: What is the relationship between the length of a beam and the am't it bends