As in Exercise 5, from a survey of coworkers you find that 48% of 200 have already received this year's fluvaccine. An approximate 95% confidence interval is (0.409, 0.551).

a) How would the confidence interval change if the sample size had been 800 instead of 200?

b) How would the confidence interval change if the confidence level had been 90% instead of 95%?

c) How would the confidence interval change if the confidence level had been 99% instead of 95%?