The mean age of all 615 used cars for sale in a newspaper one Saturday last month was 7.3 years, with a standard deviation of 7.0 years. The distribution of ages is right-skewed. For a study to determine the reliability of classified ads, a reporter randomly selects 50 of these used cars and plans to visit each owner to inspect the cars. He finds that the mean age of the 50 cars he samples is 7.9 years and the standard deviation of those 50 cars is 5.1 years. Complete parts a through c. a. From the problem statement, which of the values $7.3,7.0,7.9$, and 5.1 are parameters and which are statistics? The value 7.3 is a The value 7.0 is a The value 7.9 is a The value 5.1 is a
Solution
Step 1 ：The question is asking to identify which of the given values are parameters and which are statistics. In statistics, a parameter is a value that tells something about a whole population. A statistic, on the other hand, is a value that tells something about a sample from the population.
Step 2 ：From the problem, we know that the mean age of all 615 used cars (the whole population) is 7.3 years and the standard deviation is 7.0 years. These are parameters.
Step 3 ：The reporter then takes a sample of 50 cars and finds that the mean age is 7.9 years and the standard deviation is 5.1 years. These are statistics.
Step 4 ：So, the value 7.3 is a parameter, the value 7.0 is a parameter, the value 7.9 is a statistic, and the value 5.1 is a statistic.
Step 5 ：Final Answer: The value 7.3 is a parameter, the value 7.0 is a parameter, the value 7.9 is a statistic, and the value 5.1 is a statistic.
