Use the sample data and confidence level given below to complete parts (a) through (d). A research institute poll asked respondents if they felt vulnerable to identity theft. In the poll, n = 1081 and x = 507 who said "yes." Use a 99% confidence level. Click the icon to view a table of z scores. . . . a) Find the best point estimate of the population proportion p. 0.469 (Round to three decimal places as needed.) b) Identify the value of the margin of error E. E = (Round to three decimal places as needed.)