Explain which of the following is a statistic and which is a parameter.
a. The mean age of Americans from the 2010 decennial census
b. The unemployment rate for the population of U.S. adults, estimated by the government from a large sample
c. The percentage of Texans opposed to the health care reform bill from a poll of 1,000 residents
d. The mean salaries of employees at your school (e.g., administrators, faculty, maintenance)
e. The percentage of students at your school who receive financial aid