A New York Times article on grade inflation reported several findings related to a tendency for average grades to rise over the years and a tendency for the top-ranked institutions to give the highest average grades (Archibold, 1998). For each of the findings outlined below, state (i) the independent variable or variables, and their levels where appropriate, (ii) the dependent variable(s), and (iii) what category of research design is being used:

I-scale independent variable(s) and scale dependent variable

II-nominal independent variable(s) and scale dependent variable

III-only nominal variables

Explain your answer to part (iii).

a. In 1969, 7% of all grades were As; in 1994, 25% of all grades were As.

b. The average GPA for the graduating students of elite schools is 3.2, the average GPA for graduating students at selective schools (the level below elite schools) is 3.04, and the average GPA for graduating students at state colleges is 2.95.

c. At Dartmouth College, an elite university, SAT scores of incoming students have increased along with their subsequent college GPAs (perhaps an explanation for grade inflation).