Suppose you are given a histogram with class intervals $0-10$, $10-20$, $20-30$, and $30-40$, and the frequencies for these intervals are $5$, $12$, $18$, and $10$, respectively. What is the frequency of the modal class (the class with the most observations)?

• A. $5$
• B. $18$
• C. $10$
• D. $12$

Answer: (B)

Verified step by step guidance

1. Identify the class intervals and their corresponding frequencies from the histogram. Here, the intervals are 0-10, 10-20, 20-30, and 30-40, with frequencies 5, 12, 18, and 10 respectively.
2. Understand that the modal class is the class interval with the highest frequency, meaning it contains the most observations.
3. Compare the frequencies of all the class intervals: 5, 12, 18, and 10.
4. Determine which frequency is the greatest among these values.
5. The class interval corresponding to this highest frequency is the modal class, and its frequency is the frequency of the modal class.