In computing sample size for estimating population proportions, the formula involves p(1-p) (where we don't know p). We use p = ½ if we don't know anything about it, since that is a "worst case". Find the values of p(1-p) for p=.01, .02, .05, .10, .15, .20, .30, .40., .50, .60, .70,.80, .85, .90, .95, .98, and.99. Be prepared to graph these (this is trivial to do with Excel), and be prepared to talk about the graph.
This solution provides calculations in Excel for determining probability.