statistics

A researcher wishes to estimate, with 90% confidence, the population proportion of adults who support labeling legislation for genetically modified organisms (GMOS). Her estimate must be accurate within 3% of the true proportion. (a) No preliminary estimate is available. Find the minimum sample size needed O (b) Find the minimum sample size needed, using a prior study that found that 82% of the respondents said they support labeling legislation for GMOs (c) Compare the results from parts (a] and (b)