2. The Social Security system in the United States has encountered serious financial difficulties as baby boomers began to retire. Several polls have asked Americans their opinion about the financial condition of Social Security. In one poll, 65 percent of a sample of 1,250 non-retired persons said they did not think the Social Security system will be able to pay them a benefit when they retire. Calculate and interpret the 99 percent confidence interval to estimate the percentage of all Americans who don't think that Social Security will be able to provide for them. a. [2 points] What is the correct z score? b. [2 points] Calculate the standard error of the proportion (show your work) c. [2 points] Calculate the 99 percent confidence interval (show your work and the upper and lower estimates of the interval) d. [2 points] Interpret the confidence interval e. [2 points] What would happen to the width of your 99 percent confidence interval if the sample size increased from 1,250 to 2,000? You don't need to recalculate the problem.. .just use theory. Hint: So you're asking: "Where is the standard deviation? I need that to calculate the interval!" Remember that you only need a proportion (or percent) and N to calculate confidence intervals for proportions (or percentages). Check the formulas on the previous page