Final answer:
An English professor employing letter grades to assess the quality of essays uses an ordinal scale. This grading system ranks student performance but does not quantify the precise differences between ranks. The practice reflects a broader issue of grade inflation where expectations for certain letter grades have shifted upwards over time.
Step-by-step explanation:
An English professor uses letter grades (A, B, C, D, and F) to evaluate a set of student essays. The scale being used here is known as an ordinal scale, where the grades represent a rank order of quality but do not indicate the specific degree of difference between them. This kind of grading system is an example of a non-numeric categorization that qualitatively assesses the performance of students.
It's important to note the trend of 'grade inflation,' where the relationship between letter grades and the achievements they reflect has been changing over time. What used to earn a student a 'C' for average work can now result in a 'B' or an 'A'. In an academic setting, different subjects or instructors might have various criteria for grading essays, as seen in the rubric provided by each instructor for evaluating assignments.