Determine whether the underlined value is a parameter or a statistic; explain your reasoning.

a) A recent survey by the alumni of a major North Carolina university indicated that the average salary of an SRS of 5,000 of its graduates was $85,000.

b) The average salary of all North Carolina teachers is $53,975.

c) The average GPA for a randomly selected sample of 50 high school seniors is 54.

d) In a USA Today Internet poll, 65% of respondents said "yes" to the question "Do you consume at least one caffeinated beverage every day?"

e) The average age of a sample of 10 students in a Math 4 class is 7 years.

f) Only 69% of registered North Carolina voters voted in the 2016 presidential election.