adding distributions

I have a discrete distribution:
with a chance of a delay (in hours)
I came out of 80 000 measurements to a table with max 40 h delay and the chance of each of them occuring.
I would like to calculate what the chance is to have less delay then 12h, 24h. When I excecute 4 times the same process with the same probablity distribution.
Who could point me in the right direction?
Preferably something I can handle with Excel?
Best to fit a function?



TS Contributor
i guess the best would be to do a simulation, that should be easy enough in Excel. Generate 4 random samples of the same (large e.g 10000) size from your original data then add the first samples from all 4, the second samples and so on and then do a histogram of the sums.

thanks a lot. This was indeed quite straight forward.
I took 4 times 50 000 points and got quite a smooth graph that stayed almost the same when the randomgenerators generated again.
A multi million Euro decision will be taken based on this single graph :)