Researchers wish to compare sales of beef jerky sold at Walmart across the nation. Group $1$ consisted of stores that placed jerky packages solely in the jerky aisles. Group $2$ comprised stores that placed jerky packages in both the jerky aisles and by the checkout lanes. At the end of the year, researchers sampled and collected data on sales $($in millions$)$ to answer the question: Is the mean of Group $1$ greater than the mean of Group $2?$ The researchers used an alpha level of $0\mathrm{.}05$ in conducting the test.