Question

You toss a fair coin 4 times. What is the probability that (round to 4 decimal places)

 a) you get all Tails?

 b) you get at least one Head? 

Answer 1

Tossing a fair coin 4 times

S={ HHHH, HTHH, HHTH, HHHT, HTTH, HHTT, HTHT, HTTT, TTTT, THTT, TTHT, TTTH, THHT, TTHH, THTH, THHH}

n(S)=16

a). Probability of getting all tails

A={TTTT}

n(A)=1

b) Probability of getting at least one head

B={ HHHH, HTHH, HHTH, HHHT, HTTH, HHTT, HTHT, HTTT, THTT, TTHT, TTTH, THHT, TTHH, THTH, THHH}

n(B)=15

or

probability of getting at least one head=1-probability of not getting head at all

=1- probability of getting all tails

=1-0.0625=0.9375