The data indicating that CORe generates almost one$-$third of the total revenue for HBS Online while having only $9\%$ of the marketing budget allocated to it is crucial for accurately calculating the Return on Investment $($ROI$)$ for CORe. In the context of ROI calculation, here is the general process:

$1.**$Gather Data:$**$

$-$ Collect detailed information on the costs associated with marketing CORe, including advertising expenses, promotional costs, and any other relevant expenditures.

$2.**$Calculate Revenue from CORe:$**$

$-$ Determine the total revenue generated by CORe. This includes course fees, additional purchases, or any other sources of income associated with CORe.

$3.**$Determine CORe$-$Specific Costs:$**$

$-$ Isolate the costs specifically attributed to marketing CORe. Exclude any shared or general marketing costs not directly related to CORe.

$4.**$Calculate Marketing ROI for CORe:$**$

$-$ Use the formula for ROI: $\backslash (\backslash$text$\{$ROI$\}=\backslash$left$(\backslash$frac$\{\backslash$text$\{$Revenue$\}-\backslash$text$\{$Costs$\}\}\{\backslash$text$\{$Costs$\}\}\backslash$right$)\backslash$times $100\backslash ).$

$-$ Plug in the revenue generated by CORe and the CORe$-$specific marketing costs to calculate the ROI percentage.

$5.**$Compare with Other Courses:$**$

$-$ Refer to the ROI per course chart to compare the calculated ROI for CORe with other courses offered by HBS Online.

Understanding the specific costs associated with marketing CORe allows for a more accurate calculation of its ROI. The aim is to assess how effectively the marketing efforts translate into revenue, providing insights into the program's profitability and informing future marketing strategies.