Plot confidence bounds for route choice survey with p=0.30

[nickelanddimed]

Consider a survey of n people asking whether they plan to use Route A or Route B, with an anticipated fraction p choosing Route A.

If p = .30, plot the 95% confidence bounds and the expected value of X as a function of n, for n = 50 to n = 800.

I have no idea where to start or how to work it out..can someone please guide me through the problem.

 

[Astronuc]

There are two possible outcomes - a person chooses A or B, so a binomial distribution applies.

What have you learned about the expectation value?