Answer
a) p=0.5
b) Null hypothesis:p=0.5, alternative hypothesis: p is not 0.5.
Work Step by Step
a) The claim says that the population's proportion is equal to p=50%=0.5.
b) The null hypothesis says that the population's proportion is equal to p=0.5, whilst the alternative hypothesis says that the population's proportion is not equal to p=0.5.