Suppose a political strategist wants to get a sense of how American adults aged 18 years or

Question:

Suppose a political strategist wants to get a sense of how American adults aged 18 years or older feel about health care and health insurance.
(a) In a political poll, what would be a good frame to use for obtaining a sample?
(b) Explain why simple random sampling may not guarantee that the sample has an accurate representation of registered Democrats, registered Republicans, and registered Independents.
(c) How can stratiﬁed sampling guarantee this representation?