You may need to use the appropriate appendix table or technology to answer this question. According to the 2017 Corporate Travel Index compiled by Business Travel News, the average daily cost for business travel in the United States rose to $321 per day (Executive Travel website). The file Travel contains sample data for an analogous study on the estimated daily living costs for an executive traveling to various international cities. The estimates include a single room at a four-star hotel, beverages, breakfast, taxi fares, and incidental costs. Daily Living Daily Living City Cost ($) City Cost ($) City 1 242.87 City 11 211.00 City 2 260.93 City 12 284.08 City 3 194.19 City 1 139.16 City 4 260.66 City 14 436.72 City 5 355.36 City 15 240.87 City 6 346.32 City 16 310.41 City 165.37 City 17 223.73 City 8 250.08 City 18 181.25 City 9 326.76 City 19 238.10 City 10 283.56 City 20 250.61 (a) Compute the sample mean (in dollars). (Round your answer to the nearest cent.) (b) Compute the sample standard deviation (in dollars). (Round your answer to the nearest cent.) (c) Compute a 95% confidence interval (in dollars) for the population standard deviation. (Round your answers to the nearest cent.) to $