AZDuffman

Joined: Nov 2, 2009
• Posts: 12420
July 14th, 2010 at 7:09:01 PM permalink
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?
All animals are equal, but some are more equal than others
Wizard
Joined: Oct 14, 2009
• Posts: 23326
July 14th, 2010 at 8:56:26 PM permalink
10!/(8!*2!) * .2^8 *.8^2 = 1 in 13563.
It's not whether you win or lose; it's whether or not you had a good bet.
cclub79
Joined: Dec 16, 2009
• Posts: 1147
July 14th, 2010 at 9:13:25 PM permalink
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.
AZDuffman

Joined: Nov 2, 2009
• Posts: 12420
July 15th, 2010 at 4:05:07 AM permalink
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.
All animals are equal, but some are more equal than others