The American Association of Engineering Societies (AAES) hired Harris Interactive to conduct a survey of the American public’s knowledge of and interest in engineering. (AAES/Harris Poll “American Perspectives on Engineers and Engineering: Final Report.” 13 Feb. 2004.) The primary objective was to determine if the American public understands what engineers do and what sources of information they use to learn about engineering. Stratified random sampling was used to obtain a representative sample of 1,000 adults. In addition to answers to the survey questions, demographic information such as gender, age, education and number of engineers known was collected for each respondent. One survey item asked for responses to the statement, “ Engineers are responsible for creating things that are harmful to society”. Response categories were agree strongly, agree somewhat, disagree somewhat, or disagree strongly. An overall summary of the 965 responses is shown in the accompanying table.

a. Find and interpret a 99% confidence interval for the proportion of all American adults who disagree (somewhat or strongly) with the statement.
b. Find and interpret a 99% confidence interval for the difference between the proportions of all American adults who disagree (somewhat or strongly) and agree (somewhat or strongly) with the statement.

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HARMFUL Agree Strongly Agree Somewhat Disagree Somewhat Disagree Strongly 99 212 311 343