In Fairfax County, 6% of drivers are under 21. Last year 20
% of the drivers who are under 21 had an accident. On the other hand, only 5 %
of the drivers who are 21 or older had an accident last year. A driver is
chosen at random from Fairfax County.
Draw a tree with the probabilities labeled on the branches
to illustrate this experiment.
a. Find the probability that the chosen driver had an
accident last year.
b. Given that the driver had an accident last year, find the
probability that he is
c. Given that the driver did not have an accident last year,
find the conditional
probability that he is 21 or older.