Expected percent of randomly selected items that satisfy some property

I have a set of $n$ items and I know that $p\%$ of them satisfy some property. If I were to randomly sample $s\%$ of the items, is there a method of finding the composition of the selected items? Namely, is there a way to determine what the expected percent of the sample taken satisfies the property (call this value $d\%$)? Intuitively, it feels like there should be some relation between $n,~p,~s,\text{ and } d$ but I cannot figure out what it is (or even if one exists).

Any help would greatly appreciated.

Solution 1:

Let say that out from your $n$ items there are $m=pn/100$ satisfying some property. If your sampling is without replacement, and the sample's size is $s$, then we can use a random variable $X$ with hypergeometric distribution with parameters $n, m, s$. Namely, $X\sim Hyp(n,m,s)$; where $X$ represents the number of items from the sample satisfying the property. In this context, the expected value of the number of items satisfying the property from the sample is $$EX =\frac{sm}{n}$$