A researcher wishes to estimate, with 95% confidence, the proportion of adults who have high-speed internet access. Her estimate must be accurate within 4% of the true proportion. A) Find the minimum sample size needed, using a prior study that found that 54% of the respondents said they have high-speed internet access. B) No preliminary estimate is available. Find the minimum sample size needed.

a) What is the minimum sample size needed, using a prior study that found that 54% of the respondents said they have high-speed internet access?