Question: Parameter Versus Statistic In each of the following statements, identify the boldface number as the value of a population parameter or a sample statistic.
a. A researcher in Boston conducted a study to investigate the prevalence of Alzheimer's disease in people over the age of 85. The results indicated that 47.2% of the patients studied experienced symptoms consistent with the disease.
b. A brokerage firm reported that the mean dividend paid by all Fortune 500 companies for the year 2003 was $0.62.
c. A consumer magazine tested a random sample of 19 green teas for taste and health benefits. The mean cost per cup of tea was reported to be 14 cents.
d. A computer manufacturer claims that the mean lifetime of laptop batteries is 6.7 hours.
e. A new law requires that all propane tanks (used, for example, on barbecue grills) must have new, safer valves before they can be refilled. A gas company that refills tanks took a random sample of customers on a recent Saturday morning and reported the mean age of the propane tanks to be 3.45 years.