Simple Random Sample

You close your eyes and reach into the giant gumball glass. You pull out a green one. There are about 10,000 gumballs. It's just one sample, and you know there are 7 colors in there, but no idea how many are there of each. Somebody asks you, "What are the odds of pulling out a gumball when you reach your hand in there?" And you think, "Hmmm...wise guy." But yes, the odds are 10,000 out of 10,000 that, in this one simple, random sample, you will pull a gumball.

But what if someone told you that there are 700 gumballs in there that are lucky green? Then your odds for one sample are 700/10,000, or 7% that you pull a green. If you do pull a green (and then eat it)...then if you sample again, odds of pulling a second green are 699 out of 9,999, i.e. slightly less than the 7.00% chance you had in the previous simple random simple.

Yeah, not so simple anymore, is it?