[R] cumulative relative frequency curve(ogive)

[Fergus Lippi]

Hi, 

I have a set of experiments showing a bimodal behaviour and would like
to draw a cumulative relative frequency curve(ogive).

I would also like to read off my lower limit a the 2.5% point and the
upper at 97.5%  in oredr to have a 5% sig level.

Does anyone know if there is a function around that can perform either
of these operations.

I also know that the stepfun library has got the ecdf function which
probably only needs a few modifications to make the ogive(?)

Thank you in advance,

Fergus