Question 150427
9.  (6 pts) A couple plan to have exactly three children.  (Need line segments? Use these)
(You may also hand draw your work and scan it in and save it in your .doc  file, 
as a .jpg or .pdf. Your choice.)
(a)	Construct a tree diagram and list the sample space.
I'll let you draw the tree.
In the 1st column put "b" and "g" for boy or girl
In the 2nd column put "b" and "g" to the right of each of the column 1 entries
In the 3rd column put "b" and "g" to the right of each of the column 2 entries 
  	                              
(b) Find the probability that the family has at least two girls.
at least two girls: bgg, gbg, ggb, ggg
P(at least two g's)= 4/8 = 1/2
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Cheers,
Stan H.