Answer :
This can be solved by using the binomial distribution:
[tex]P(8\ heads)=19C8\times(\frac{1}{2})^{8}\times(\frac{1}{2})^{11}=0.144[/tex]
[tex]P(8\ heads)=19C8\times(\frac{1}{2})^{8}\times(\frac{1}{2})^{11}=0.144[/tex]