Given the following frequency distribution for exam scores: $50-59$: $3$ students, $60-69$: $5$ students, $70-79$: $8$ students, $80-89$: $4$ students, which of the following represents the correct cumulative frequency for the class interval $70-79$?

• A. $8$
• B. $12$
• C. $16$
• D. $5$

Answer: (C)

Verified step by step guidance

1. First, understand that the cumulative frequency for a class interval is the total number of observations up to and including that interval.
2. Identify the frequencies for all class intervals up to and including 70-79: 50-59 has 3 students, 60-69 has 5 students, and 70-79 has 8 students.
3. Add these frequencies together to find the cumulative frequency for the 70-79 interval: calculate \$3 + 5 + 8$.
4. This sum represents the total number of students who scored 79 or below, which is the cumulative frequency for the 70-79 class interval.
5. Compare this cumulative frequency with the given options to determine the correct answer.