With the increased use of credit cards, debit cards, and other electronic methods of payment, will the United States eventually stop using cash? In a July 2016 Gallup poll of a random sample of 1,024 U.S. adults, 635 of them thought the United States would become a cashless society in their lifetimes. 

a. Identify the parameter estimated by the poll. 

b. Verify the validity conditions for a theory-based confidence interval. 

c. Find a theory-based 95% confidence interval for the population parameter and interpret the confidence interval you obtained in the context of the problem. 

d. Based on your confidence interval, is there strong evidence that the proportion of Americans who think the United States would become a cashless society in their lifetime is different than 0.65? Explain how you are determining this.