A survey of 1,000 adults was conducted in March 2009 concerning "green practices." In response to the question of what was the most beneficial thing to do for the environment, 28% said buying renewable energy, 19% said using greener transportation, and 7% said selecting minimal or reduced packaging. (Data extracted from "Environmentally Friendly Choices," USA Today, March 31, 2009, p. D1.) Construct a 95% confidence interval estimate of the population proportion of who said that the most beneficial thing to do for the environment was
a. Buy renewable energy.
b. Use greener transportation.
c. Select minimal or reduced packaging.
d. You have been asked to update the results of this study. Determine the sample size necessary to estimate, with 95% confidence, the population proportions in (a) through (c) to within ± 0.02.