Problem $2$: Gap Sales

Table $2$ presents the Gap's quarterly sales data for $1985$ Q$1$

through $2006$ Q$4.$ Analyze the data and answer the following

questions:

$2\mathrm{.}1.$ Create a time$-$series plot of the Gap Sales. Describe the

pattern$($s$)$ of the time series you see in the graph.

$2\mathrm{.}2$ Calculate the seasonal factors $($SI$)$ and then the seasonal

indices $($S$)$ based on the $1985$ Q$1-2006$ Q$4$ data. Are they

consistent with your expectations? Explain in detail.