In a random sample of 8 people, the mean commute time to work was 36.5 minutes and the standard deviation was 7.3 minutes. A 95% confidence interval using the t-distribution was calculated to be (30.4,42.6). After researching commute times to work, it was found that the population standard deviation is 9.3 minutes. Find the margin of error and construct a 95% confidence interval using the standard normal distribution with the appropriate calculations for a standard deviation that is known. Compare the results. The margin of error of u is (Round to two decimal places as needed.)