In a single toss, the probability that the result of the toss is head is 1/2:
[tex]P_1 (head) = \frac{1}{2} [/tex]
For 2 tosses in a row, the probability that the result is head in both tosses is
[tex]P_2 = P_1 \cdot P_1 = ( \frac{1}{2} )( \frac{1}{2} )= \frac{1}{4} [/tex]
If we continue, we find that the probability to have 4 heads in 4 consecutive tosses is given by
[tex]P_4 = ( P_1 (head) )^4 = ( \frac{1}{2} )^4 = \frac{1}{16} [/tex]
