Question 933559
a group of students have 3 desktop computers and 3 laptop computers. they want to select 2 computers at random for a course project. 
Let X be the number of laptop computers in the selection.
how many ways can the students select two computers from six? 6C2 = 15
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what is the probability of selecting X=2 laptop computers?
P(x = 2) = 3C2/6C2 = 3/15 = 1/5
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 construct a probability distribution table for X? 
P(x = 0) = (3C0*3C2)/6C2 = (1*3)/6C2 = 1/5
P(x = 1) = (3C1*3C1)/6C2) = 9/15 = 3/5
P(x = 2) = (3C2)(3C0)/6C2 = 1/5
find the variance of X?
Ans: 2/3
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Cheers,
Stan H.
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