8.19 The file AirportRating contains the rating of large and medium size airports in the United States and Canada. Source: Data extracted from N. Trejos, "Portland, Indianapolis Top Airport Rank- ings, USA Today, December 16, 2016, p. 4B. For large and medium airports separately: a. Construct a 95% confidence interval estimate for the population mean rating. b. Interpret the interval constructed in (a). c. What assumption must you make about the population distribu- tion in order to construct the confidence interval estimate in (a)? d. Do you think that the assumption needed in order to construct