Let's say you have 100 marbles in a jar, one of them is unique. The chances of that "one" being picked would be 1/100 or 1%. Now let's say you picked a handful of marbles, 16 at a time, what would be the probability that that unique "one" would get picked again? My guess is 100/16 = 6.25, and then 1/6.25 or 16%. Is this correct? What would the technical term for this type of grouping probability be? thanks!