Problem $2$

Amazon.com, Inc., was a money$-$losing company when it went public on May $15,1997,$ with an IPO valued at a modest $$438$ million. Amazon has since had an epic run as a public company, worth over a trillion dollars in $2020.$ An important question for investors and other stakeholders is if Amazon's growth is sustainable. The accompanying spreadsheet, in the tab titled "RevenueAmazon", contains quarterly data on Amazon's revenue for the fiscal years $2010$ through $2020,$ with the fiscal year concluding at the end of December.

$($a$)$ Fit two models of your choice. Explain why you chose those models. Note: "Fitting" a model means using Solver to find the best model parameters.

$($b$)$ Use your preferred model to forecast Amazon's revenue for fiscal year $2021.$ Why did you choose that model?