sampling -VBA code

[rbarroet]

I have this problem. I have to analyze 13 substances (n=13) in more than one analysis cycle. In each cycle of analysis 8 substances are randomly chosen (m=8). How many analysis cycles are needed for each of the 13 substances to be analyzed at least once with a probability of 99% (alpha=0.99). I did the experiment manually and it takes 4 analysis cycles. I would like a VBA code that allows me to estimate the cycles with the information of "n", "m" and "alpha".
Thank you,
Roberto