Since 2007, a psychological association has supported an annual nationwide survey to examine stress across the United States. One year, a total of770millennials(18- to33-year-olds) were asked to indicate their average stress level (on a10-pointscale) during a month. The mean score was 5.5. Assume that the population standard deviation is2.6.

Give the margin of error for a 95% confidence interval. (Enter your answer to three decimal places.)

Find the 95% confidence interval for this sample. (Enter your answers to three decimal places.) (_____,_____)

Give the margin of error for a 99% confidence interval. (Enter your answer to three decimal places.)

Find the 99% confidence interval for this sample. (Enter your answers to three decimal places.) (_____,_____)

How do the results compare with those in part (a)?