fair quarter flipped thrice For each probabilities,formula.look in binomial probability table

Question

A fair quarter is flipped three times. For each of the following probabilities, use the formula for the binomial distribution and a calculator to compute the requested probability. Next, look up the probability in the binomial probability distribution table

Answer 1

n=3, p=1-p=1/2.

Binomial expansion: "1 3 3 1" p^3, 3p^2(1-p), 3p(1-p)^2, (1-p)^3: 1/8, 3/8, 3/8, 1/8.

Table gives: P(3H)=P(3T)=0.125; P(2H,1T)=P(1H,2T)=3/8. (H=head, T=tail).

P(2H,1T or 1H,2T)=3/8+3/8=3/4.

P(at least one head)=1-P(no heads)=1-1/8=7/8=P(at least one tail).