A committee of 3 is to be selected randomly from a group of 3 men and 2 women.
Let X represent the number of women on the committee. Find the probability
distribution of X.

Answer :

LammettHash

Total number of ways to select 3 people from the 5 total: 5!/(3! (5 - 3)!) = 10

• Number of ways of picking 0 women:

[tex]\dbinom20\times\dbinom33 = 1\times1 = 1[/tex]

• Number of ways of picking 1 woman:

[tex]\dbinom21\times\dbinom32 = 2\times3 = 6[/tex]

• Number of ways of picking 2 women:

[tex]\dbinom22\times\dbinom31 = 1\times3 = 3[/tex]

• Number of ways of picking 3 women: 0, since there are only 2 to choose from

Then X has the probability mass function

[tex]P(X=x) = \begin{cases}\frac1{10}&\text{if x=0}\\\frac6{10}=\frac35&\text{if }x=1\\\frac3{10}&\text{if }x=2\\0&\text{otherwise}\end{cases}[/tex]

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