7 Did You Use a Mobile Device? The Monterey Bay Aquarium, founded in 1984, is situated on the beautiful coast of Monterey Bay in the historic Cannery Row district. In 1985, the aquarium began a survey program that involved ran- domly sampling visitors as they exit for the day. The survey includes visitor de- mographic information, use of social media, and opinions on their aquarium visit. In 2015, the survey included 356 visitors over age 65, of which 52 used a mobile device such as an Android phone or iPad during their visit." (a) What is the margin of error of the large-sample 95% confidence interval for the proportion of visitors over 65 who used a mobile device during their visit? (b) How large a sample is needed to get the common 3 percentage point margin of error? Use the 2015 sample as a pilot study to get p*.