6.18 Is college worth it? Part II: Exercise 6.16 presents the results of a poll where 48% of 331 Americans who decide to not go to college do so because they cannot afford it. (a) Calculate a 90% confidence interval for the proportion of Americans who decide to not go to college because they cannot afford it, and interpret the interval in context. lower bound: 0.4350 upper bound: 0.5250 (please round to four decimal places) (please round to four decimal places) Interpret the confidence interval in context: 90% of Americans choose not to go to college because they cannot afford it We can be 90% confident that the proportion of Americans who choose not to go to college because they cannot afford it is contained within our confidence interval We can be 90% confident that our confidence interval contains the sample proportion of Americans who choose not to go to college because they cannot afford it (b) Suppose we wanted the margin of error for the 90% confidence level to be about 1.5%. How large of a survey would you recommend? A surkey should include at least x people.