Odds on number of smokers in a work group?

At the risk of this sounding like an "'a' chasing'b'" Algebra problem, I will word it simply. How long the odds are has been driving me crazy.

I work in a work-group of 10 people. Of these 10 people, 8 are smokers. If we assume the smoking rate in the USA is about 20% of adults, what are the odds that 8 of 10 people in a work group are smokers? (Ignore the dact that different age, race, or sex can affect rates, use the straight 20% average across the adult population.)

How would I figure this one out?

10!/(8!*2!) * .2^8 *.8^2 = 1 in 13563.

Not to upend your formula, and more to just shoot the bull, but I bet it's more than 20%. People like to say they don't smoke when they actually do (as I've found out on several dates). I also think gender and race aren't a large determinant, but I have a feeling regionality in the US is an important variable. The social acceptance that gets young people into smoking is vastly different in different places around the country.

Quote: cclub79

Not to upend your formula, and more to just shoot the bull, but I bet it's more than 20%. People like to say they don't smoke when they actually do (as I've found out on several dates). I also think gender and race aren't a large determinant, but I have a feeling regionality in the US is an important variable. The social acceptance that gets young people into smoking is vastly different in different places around the country.

I used 20% based on reading it a few times, like here www.reuters.com/article/idUSTRE4AC6XX20081113.

Not sure on gender or race, but breaking my group down we are more female heavy but mostly about where the USA is racially, except no Asians. However, I am fully aware having 2 members represent one minority each is not accpetable to project. But it is just kind of interesting.

Thnaks, Wiz, for the quick and detailed reply.