SOLUTION: An urn contains 3 red and 2 white numbered balls. A sample of 2 balls is randomly chosen. Find the average number of red balls in the sample.

Question 245770: An urn contains 3 red and 2 white numbered balls. A sample of 2 balls is randomly chosen. Find the average number of red balls in the sample.
Answer by stanbon(75887) (Show Source): You can put this solution on YOUR website!
An urn contains 3 red and 2 white numbered balls. A sample of 2 balls is randomly chosen. Find the average number of red balls in the sample.
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Average means "the expected number".
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Random variable vales: 0,1,2
Corresponding probabilities:
P(x=0) = 3C0/5C2 = 1/10
P(x=1) = 3C1*2C1/5C2 = 6/10
P(x=2) = 3C2/5C2 = 3/10
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E(X) = 0*(1/10) + 1*(6/10) + 2*(3/10) = (0+6+6)/10 = 1.2 red balls
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Cheers,
Stan H.
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