Five fair coins are tossed. Find the probability of obtaining 4 heads and 1 tail.
Possible solutions:
1/32
3/32
4/32
5/32
This is a binomial distribution problem. Probability of success on single trial
(a head on one toss) p=0.5. Number of trial n=5, number of successes of
interest k=4.
Then the required probability is:
f(k;n,p)=C(n,k) p^k (1-p)^(n-k)
which in this case is:
f(4;5,4)=5 (0.5)^4 (0.5)=0.15625
or about 15.6%.
RonL