Final answer:
The mean amount spent on produce per visit ($12.84) is an example of a statistic, which is a characteristic of a sample from a study.
Step-by-step explanation:
The metric used in the Proposition Distribution report is not explicitly mentioned in the provided context. However, when analyzing data related to sales, finance or customer behaviors, typically metrics such as volume, target budget, total revenue, and accept rate might be considered, depending on the specific report's purpose. For the study mentioned, which finds that the mean amount spent on produce per visit by the customers in the sample is $12.84, this is an example of a statistic. A statistic is a characteristic of a sample, whereas a parameter is a characteristic of a population. The mean amount here is derived from a sample of the total customer base and not the entire population, which makes it a statistic.