An example of an ________________ target variable is value of purchase, which is useful for modeling the best customers for particular products, catalogs, or sales campaigns.

The correct answer is interval. An interval target variable is one where the differences between values are meaningful and consistent, allowing for the measurement of how much more one value is compared to another. In this context, the value of purchase is a quantitative measure that reflects the amount spent by a customer. This variable can have a meaningful zero point and the distances between different purchase amounts convey actionable insights, such as identifying high-value customers or assessing the success of marketing campaigns.

Interval variables are particularly valuable in modeling scenarios where understanding the magnitude of different ranges of values is crucial, such as determining the best customers for specific products. This level of measurement allows for various statistical analyses and can be used to predict future purchases, enhance targeting strategies, and tailor marketing efforts for optimal effectiveness.

In contrast, ordinal variables represent categories with a meaningful order but without quantifiable differences between them, binary variables consist of two categories (e.g., yes/no), and nominal variables classify data without any implicit numerical relationship. Therefore, these options wouldn’t apply in the context of measuring purchase value, making interval the most relevant choice for this scenario.