The mean age of all 618 used cars for sale in a newspaper one Saturday last month was 7.7 ​years, with a standard deviation of 7.3 years. The distribution of ages is​ right-skewed. For a study to determine the reliability of classified​ ads, a reporter randomly selects 30 of these used cars and plans to visit each owner to inspect the cars. He finds that the mean age of the 30 cars he samples is 8.3 years and the standard deviation of those 30 cars is 5.7 years. Required:
From the problem​ statement, which of the values 7.7​, 7.3​, 8.3​, and 5.7 are parameters and which are​ statistics?