meet the ladies!

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Meet the ladies!. But…are they all ladies?. P(“female” chick is actually female) = 0.9. We selected 4 chicks (from over 500 in the store). Independent or dependent sampling?. P(all hens). P(all roosters). P(1 rooster, 3 hens ). hmmmmmmm ….  hens per group of 4. - PowerPoint PPT Presentation

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P(“female” chick is actually female) = 0.9

We selected 4 chicks (from over 500 in the store)

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Binomial Random Variables

1) …a fixed number of independent trials…

Binomial experiments have…

For this exercise, it’s the 4 chicks (arguably independent).2) …two mutually exclusive outcomes per

trial… A chick is either male or female.

3) …and constant, complementary probabilities from trial to trial.

P(female) = 0.9

P(male) = 0.1

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Does this describe a binomial experiment?

Rolling a single die, and counting the pips you get.

Roll a single die. If you roll 3, you win $4.

If not, you lose $1.

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Does this describe a binomial experiment?

Rolling two dice, and summing the pips you get.

Rolling two dice, and betting on 7 or 11.

Rolling two dice 5 times, and betting on 7 or 11 each time.

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Does this describe a binomial experiment?

Betting on “5” in Chuck – A – Luck.

Buying 4 Oregon Cash Cow Bingo Scratchoffs for

2$ each. (overall chance of winning

per ticket: 1 in 3.54)

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Does this describe a binomial experiment?

About 7% of American men have red/green color blindness (RGCB). You select 20 at random and check

to see how many have RGCB.

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Does this describe a binomial experiment?

About 7% of American men have red/green color blindness (RGCB). You keep selecting men at random

until you’ve found 20 that have RGCB.

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Does this describe a binomial experiment?

About 7% of American men have red/green color blindness (RGCB).

I think this class has the same proportion. I select 10 men at

random from this class and check them for RGCB.

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…Max, summer 2010…

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Assume Max is guessing when he puts his Crocs on, and assume he tries 10 times...is

that a binomial experiment?

Cool aside: for a binomial RV, m= np

(n = number of trials, p = chance of success on one trial)

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Assume Max is guessing when he puts his Crocs on, and assume he tries 10 times…

Cool aside (2) : for a binomial RV,

(q = chance of failure on one trial)

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Assume Max is guessing when he puts his Crocs on, and assume he tries 10 times…

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(a 244 – ish question)... in 10 tries, he got his Crocs on the correct feet only once. Based on your previous answers, do you think he’s guessing

when he puts his Crocs on? Why or why not?