ISTQB Certified Tester Foundation Level (CTFL 2018) — Question 43

A class grade application for instructors assigns letter grades based on students’ numerical grades. The letter grades for different numerical grades should be:

Above 89, up to 100 - A -

Above 79, up to 89 - B -

Above 69, up to 79 - C -

Above 59. up to 69 - D -

Below 60 - F -

Which of the following sets of test inputs would achieve the relatively highest equivalence partition coverage?

Answer options

• A. 0, 58, 59, 70, 80
• B. 69, 79, 80, 89, 90
• C. 74, 79, 84, 85, 89
• D. 79, 89, 90, 99, 100

Correct answer: D

Explanation

Option D is the correct choice as it includes values that cover the upper boundaries of the grading ranges, ensuring a comprehensive test of the grading logic. The other options do not effectively cover all the critical ranges needed for thorough testing, particularly the highest grade segments.