A man approaches a shepherd, and bets him $100 against a sheep from the flock, that he can, in one guess, estimate how many sheep are in the flock.
The shepherd knows he has nearly a thousand sheep, and figures it will be hard for this suited man to come anywhere near the correct number. So, thinking of what he can spend the $100 on, he agrees to the bet.
The suit looks over the flock, hems and haws for a minute, mutters to himself 'add 10 for wanderers betweeen subgroups and divide by coefficient of density'... then turns to the shepherd : "979".
"That's....that's Exactly right! By god I don't know how you did it but you've won fair and square."
The suit grabs an animal from the flock and is turning to go when the shepherd says: "WAIT!! I'll bet you double or nothing, that I can guess your occupation!"
The suit agrees, and the shepherd says "Government economist."
"Yup." says the economist. "How did you know?
"Well, I had a real good clue when you picked up my dog there...."