2. Tinaville is a medium-size affluent town in the heartland of the country of Metaluna that prides Itself on having the best retirement portfolio. You wish to estimate, with 88% confidence, the population proportion of Tinaville's Adults who think they have a comfortable retirement portfolio. Your estimate must be accurate within 6.85 % of the true population proportion. (Show all calculations and steps) a. What is the minimum number of Tinavillois adults you need to sample if no preliminary estimate is available? b. Find the minimum sample size needed, using a prior estimate that found that 68.5% of Tinaville's adults think that they have a comfortable retirement portfolio.