I know the unconditional variance formula of the form:
((n)(r)(N-r)(N-n)) / ((N)(N)(N-1))
So, what is the variance formula conditioned on 1 or 2 items - particularly when there's 3 different items to choose from ?
I know the unconditional variance formula of the form:
((n)(r)(N-r)(N-n)) / ((N)(N)(N-1))
So, what is the variance formula conditioned on 1 or 2 items - particularly when there's 3 different items to choose from ?