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?

Overproduction of uric acid in the body can be an indication of cell breakdown. this may be an advance indication of illness such as gout, leukemia, or lymphoma.† over a period of months, an adult male patient has taken nine blood tests for uric acid. the mean concentration was x = 5.35 mg/dl. the distribution of uric acid in healthy adult males can be assumed to be normal, with σ = 1.87 mg/dl. (a) find a 95% confidence interval for the population mean concentration of uric acid in this patient's blood. what is the margin of error? (round your answers to two decimal places.) lower limit upper limit margin of error (b) what conditions are necessary for your calculations? (select all that apply.) σ is unknown n is large σ is known normal distribution of uric acid uniform distribution of uric acid (c) interpret your results in the context of this problem. there is not enough information to make an interpretation. the probability that this interval contains the true average uric acid level for this patient is 0.05. the probability that this interval contains the true average uric acid level for this patient is 0.95. there is a 95% chance that the confidence interval is one of the intervals containing the population average uric acid level for this patient. there is a 5% chance that the confidence interval is one of the intervals containing the population average uric acid level for this patient. (d) find the sample size necessary for a 95% confidence level with maximal margin of error e = 1.10 for the mean concentration of uric acid in this patient's blood. (round your answer up to the nearest whole number.) blood tests