In July 2015, a poll asked a random sample of 1,236 registered voters in Iowa whether they agree or disagree that the world needs to do more to combat climate change. The results show that $65\%$ agree, while $25\%$ disagree and $10\%$ don't know.

(a) What is the sample? What is the intended population?

(b) Is it reasonable to generalize this result and estimate that $65\%$ of all registered voters in Iowa agree that the world needs to do more to combat climate change?