Probability of picking Marbles in a bag?

For this problem, use the Hypergeometric Probability Formula:

P(x) = [(sCx)*(N-sCn-x)] / NCn

where:

N = is the size of the population (9)

s = is the number of successes in the population (2)

x = is the number of successes in the sample (2)

n = is the size of the sample or the number of trials (3)

C = is the symbol for a Combination

P(x) = [(sCx) * (N-sCn-x)] / NCn

P(2) = [(2C2) * (9-2C3-2)] / 9C3

P(2) = [(2C2) * (7C1)] / 9C3

P(2) = [(1) * (7)] / 84

P(2) = [7] / 84 = 1/12 or 0.0833

Yeah, the math gets really messy,

but you can use an online Hypergeometric Probability Calculator:

http://stattrek.com/Tables/Hypergeometric.aspx

To answer an earlier question, there's no built in function for the TI-83/84,

but this is as close as it gets:

http://mathbits.com/MathBits/TISection/Statistics2...

Good luck in your studies,

~ Mitch ~

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Marble Probability Calculator

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