Suppose a fair coin is tossed 4 times. Write out all four outcomes (TTHH, etc). What is the
probability ...
of obtaining four heads, of obtaining two heads and two tails, obtaining no heads, and of
obtaining at least one head?
Solution
Sample space: 0 tails, 4 heads: HHHH 1 tails, 3 heads HHHT HHTH HTHH
THHH 2 tails, 2 heads HHTT HTHT HTTH THHT THTH TTHH 3 tails, 1 heads TTTH TTHT
THTT HTTT 4 tails, 0 heads TTTT So 16 total possibilities. Probability of... A) four heads = 1 /
16 B) two heads and two tails = 6 / 16 C) obtaining no heads = 1 / 16 D) and of obtaining at least
one head? = 15 / 16