A research center conducted a telephone survey of 2,000 adults to learn about the major economic concerns for the future. The survey results showed that 1,780 of the respondents think the future health of Social Security is a major economic concern.   (a) What is the point estimate of the population proportion of adults who think the future health of Social Security is a major economic concern?   (b) At 90% confidence, what is the margin of error? (Round your answer to four decimal places.)   (c) Develop a 90% confidence interval for the population proportion of adults who think the future health of Social Security is a major economic concern. (Round your answer to four decimal places.)   (d) Develop a 95% confidence interval for this population proportion. (Round your answer to four decimal places.)

alo Smart phone: Among 248 cell phone owners aged 18-24 surveyed, 104 said their phone was an Android phone. Part: 0 / 3 Part 1 of 3 (a) Find a point estimate for the proportion of cell phone owners aged 18-24 who have an Android phone. Round the answer to at least three decimal places. The point estimate for the proportion of cell phone owners aged 18-24 who have an Android phone is Part: 1/3 Part 2 of 3 (b) Construct a 99.5% confidence interval for the proportion of cell phone owners aged 18-24 who have an Android phone. Round the answers to at least three decimal places. A 99.5% confidence interval for the proportion of cell phone owners aged 18-24 who have an Android phone is