According to the Pew Research Center, in 2015, 19% of all American adults had Twitter accounts. Suppose this is true now. 

a. If a random sample of 500 Americans is taken, use the normal approximation to the binomial distribution to determine the probability that between 19% and 22% of the sample has a Twitter account. 

b. How does your answer to part (a) compare to your answer to Exercise 11.8.10(a)? Explain why this makes sense.

Data from Exercises 11.8.10

According to the Pew Research Center, in 2015, 19% of all American adults had Twitter accounts. Suppose this is true now. If a random sample of 500 Americans is taken, use the normal approximation to the binomial distribution to determine the probability that between 17% and 21% of the sample has a Twitter account.