Question: In early September, 2003, California's Governor Gray Davis approved a controversial law allowing people who were not legal residents to obtain a California state driver's license. That week the California Field Poll released a survey showing that 59% of registered voters opposed the law and 34% supported it. This part of the survey was based on a random sample of just over 300 people.
a. What is the approximate margin of error for the Field Poll results?
b. Provide an interval that is likely to cover the true percentage of registered California voters who supported the law.