IMathAS-libretexts

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: (please round to four decimal places)
upper bound: (please round to four decimal places) Interpret the confidence interval in context:

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
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
90% of Americans 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 survey should include at least people.

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