Let's revisit the cumulative gains chart below from our previous class, which was used to analyze a marketing campaign to gain new customers. Can you explain and interpret this chart briefly? Based on what you see, what percentage of customers ought to be contacted to get an optimal number of positive responses?"

elow the question, there is a "Cumulative Gains Chart" that has two lines: a "Lift Curve" marked by a dashed line with magenta diamond markers, and a "Baseline" which is a solid line. The chart is a grid layout with the x$-$axis labeled $"\%$ Customers Contacted" running from $0$ to $100$ and the y$-$axis labeled $"\%$ Positive Responses" also running from $0$ to $100.$ The Baseline appears to be a straight line from the origin $(0,0)$ to the top right corner $(100,100),$ representing a scenario where the percentage of positive responses is directly proportional to the percentage of customers contacted.

The Lift Curve starts at the origin and rises more steeply than the Baseline, indicating that targeting customers based on the model leads to a higher percentage of positive responses compared to a random selection. However, without seeing where the Lift Curve plateaus or changes slope, it is not possible to determine the exact percentage of customers that should be contacted for an optimal number of positive responses just from this snippet of the image. Typically, the optimal contact point is where the Lift Curve starts to plateau or the incremental gains decrease substantially.