Normalising a probability density function

Aug 2010
Hi All,
a newbie here to this forum and in need of some help since it's a long time since I studied statistics!

I am trying to duplicate some work described in a conference paper. I have sample data which I have used to plot a normal probability curve using the actual standard deviation and mean of the data. However the paper requests me to use a normalized probability density.... I assume that this means that the area under the curve should equal 1.

I know that I can split the bottom axes into a series of bins and sum each of the individual areas and set it equal to 1. My question is does anyone have an easier method of doing this since I can imagine this is a fairly standard question?

I ultimately plan to implement this in Matlab but don't have the full statistics module so am looking for a work-around to prove the concept that I am working on.

Any help/advice would be greatly appreciated,