a. Sample: 3,318 American children age 10 through 12 b. Variable: Body Mass Index (BMI) c. Parameter of interest: Mean BMI of American children age 10 through 12 d. Statistic: The mean BMI of the sample of 3,318 children in the study. Explanation: a. Sample: The group of 3,318 children in the age range of 10 through 12 who were enrolled in the study is considered the sample. The sample is a subset of the population of all American children age 10 through 12 and is used to represent the population and make inferences about it. b. Variable: Body Mass Index (BMI) is the variable being measured in the study. It is a measure of body fat based on a person's weight and height. c. Parameter of interest: The mean BMI of American children age 10 through 12 is the parameter of interest in the study. A parameter is a characteristic of a population, and in this case, the study is interested in finding the average BMI for the population of American children age 10 through 12. d. Statistic: The mean BMI of the sample of 3,318 children in the study is a statistic. A statistic is a characteristic of