Indicate which of the following situations involve descriptive statistics and which involve inferential statistics:
a. An annual stockholders' report details the assets of the corporation.
b. A history instructor tells his class the number of students who received an A on a recent exam.
c. The mean of a sample set of scores is calculated to characterize the sample.
d. The sample data from a poll are used to estimate the opinion of the population.
e. A correlational study is conducted on a sample to determine whether educational level and income in the population are related.
f. A newspaper article reports the average salaries of federal employees from data collected on all federal employee