Tree Diagrams
Probability Trees
A family has three children. Let’s assume each child is equally likely
to be a boy or a girl.
a) Draw a probability tree to show all possible outcomes.
b) What is the probability of two of the three children being girls?
½
½
½
½
B
B
½
½
G
B
½
½
½
½
G
1st child
G
½
½
G
2nd child
B
B
BBB
BBG
BGB
G BGG
B GBB
½
G
B
GBG
GGB
½
G GGG
3rd child
ADD
down
the
tree