Population is the total population.

$n$ the number of elements in group $A$.

Sample is the sample size, that is, the number of elements you draw.

If you’re asked to compute the probability of getting exactly $k$ elements from $A$, you can find it in the table on the right-hand side.

If you’re asked to compute the probability of getting at least $k$ elements from $A$, choose Right-sided  and enter the value of $k$.

If you’re asked to compute the probability of getting at most $k$ elements from $A$, choose Left-sided  and enter the value of $k$.

If you’re asked to compute the probability that the number of elements drawn from $A$ will be between $N$ and $M$, including $N$ and $M$, choose Interval  and enter the values of $N$ and $M$.

If you’re asked to compute the probability that the number of elements drawn from $A$ is not between $N$ and $M$, choose Two tailed and enter the values $N-1$ and $M+1$. Alternatively, you can compute the probability in the item above, and then take it and subtract it from 1.