Data: airfare.csv (download from Module 4 on Brightspace) Every quarter, the Bureau of Transportation Statistics (BTS) takes a survey to track domestic airfares. This time series shows average airfares calculated from BTS (inflation adjusted to 2018 dollars) for U.S. domestic flights from 2004 to 2018. Background: For this part of the assignment, you work for a large airline (in 2018) and you would like to forecast 2019 average annual airfare in order to inform your airline's pricing strategy. Your business question is: "What is a reasonable forecast of 2019 average U.S. domestic airfare given the patterns in past data?" Assignment Steps: Carry out the steps for Part 1 below to complete the assignment, then answer the questions in the Module 4 Assignment Quiz, Part 1, on Brightspace. The quiz questions are included here, with their numbers, if you prefer to answer them as you are doing the assignment and enter them in the Brightspace quiz all at once (multiple choice questions are labeled "MC"). Create a time series plot of the average airfare data. Quiz question #1: What patterns do you notice in the time series plot of average annual airfare? (MC)