Texts: Harini is an undergraduate student who is interested in doing a summer internship in Statistics or a related field. Looking at the internship announcements on the American Statistical Association's (ASA) website, she sees that in Industry, most internships are only offered to graduate students. However, Academia, Government, and Non-profit research organizations have more listings for undergraduates. Round all calculated answers to 4 decimal places where appropriate.
1. Harini sees that the proportion of undergraduate internship postings for all four fields in 2017 was 38.9%. Using this as a planning value, she wants to estimate the proportion for the upcoming summer at 95% confidence and a margin of error of no more than 2.2%. How many internship postings would Harini need to sample to accomplish this?
NOTE: Round your 𝑧 value to exactly 3 decimal places for this calculation.