A survey of 1000 adults was conducted concerning "green practices". In response to a question of what was the most beneficial thing to do for the environment, 28% said "buying renewable energy".
a) Predict what percentage of the population of adults would answer this way if they were all asked. You would like to be 95 percent confident you will be correct.
b) Next year you will repeat this study. Determine the sample size necessary to estimate, with 95% confidence, the population percentage to within plus and minus 0.02 or 2%.