## Elementary Statistics (12th Edition)

a)$\bar{A}$ means the complement of A, that A doesn't occur. Hence here it means the event of selecting someone who doesn't think that college isn't a good investment. b)$P(\bar{A})=1-P(A)=1-0.1=0.9=90$%. c)By using the multiplication rule: $P(AAA)=P(A)\cdot P(A) \cdot P(A)=0.1^3=0.001.$ d)Here the sampling uses a voluntary response orthe population's subgroup hence it is a convenience sample. Hence the survey cannot be used to represent the whole population, because not everybody has the chance to participate in it.