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Four children were born at City Hospital yesterday. Assume each child is equally likely to be a boy or a girl. Which of the following outcomes is most likely?

 Dec 29, 2015

Best Answer 

 #1
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+12

1)-The probability that 2 are girls and 2 boys =37.50%

2)-The probability that 3 are girls and 1 boy   =25.00%-The same holds true for 3 boys and 1 girl.

3)-The probability that 4 are girls and no boys=6.25% -The same holds true for 4 boys and no girls.

The formula used for the above odds is: N! / [B!*G!] / 2^N, where N=number of children, B=number of boys, G=number of girls.

 Dec 29, 2015
 #1
avatar
+12
Best Answer

1)-The probability that 2 are girls and 2 boys =37.50%

2)-The probability that 3 are girls and 1 boy   =25.00%-The same holds true for 3 boys and 1 girl.

3)-The probability that 4 are girls and no boys=6.25% -The same holds true for 4 boys and no girls.

The formula used for the above odds is: N! / [B!*G!] / 2^N, where N=number of children, B=number of boys, G=number of girls.

Guest Dec 29, 2015
 #2
avatar+118608 
+10

P(All girls)=P(all boys)=4C4*0.5^4 = 

 

\(P(All\; girls)=P(all\; boys)=4C_4*(\frac{1}{2})^4 = 1*\frac{1}{16}=\frac{1}{16}\\~\\ P(1\; girls,\;3\;boys)=P(3\; boys,\;1\;girl)=4C_1*(\frac{1}{2})^4 = 4*\frac{1}{16}=\frac{4}{16}=\frac{1}{4}\\~\\ P(2\; girls,\;2\;boys)=4C_2*(\frac{1}{2})^4 = 6*\frac{1}{16}=\frac{6}{16}=\frac{3}{8}\\~\\\)

Check

1/16+1/16+1/4+1/4+3/8 = 1

That is excellent :)

 Dec 29, 2015
 #3
avatar+128460 
0

Thanks, Melody......I see this easier as a binomial probability problem, too.......however......the formula that the guest has provided might be worth exploration......!!!!

 

 

cool cool cool

 Dec 29, 2015
 #4
avatar+118608 
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Our guest HAS used the binomial formula too Chris      LOL

 Dec 29, 2015
 #5
avatar+128460 
0

Ah, yes......I see now that it IS the binomial formula........!!!!!

 

A simple case of CDD for me......maybe Nauseated could prescribe a tonic......!!!!!!

 

 

cool cool cool

 Dec 29, 2015

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