In a sample of 610 boston-area residents selected on july 2, 209 reported that they were planning to travel beyond massachusetts for the july 4th holiday.
(a) use these data to find a 95% confidence interval for the proportion (p) of all boston-area residents who plan to travel beyond massachusetts for the holiday. [you may assume that the sample is random.]
(b) repeat part (a) but compute a 90% confidence interval for p.
(c) repeat part (a) but compute an 80% confidence interval for p.
(d) explain how the margins of error associated with your intervals in parts (a), (b), and (c) vary with the level of confidence (c) desired.