California Assessment of Student Performance and Progress (CAASPP) Math Practice Exam

What is the mode in a set of numbers?

1. The average of the numbers

2. The number that occurs most frequently

3. The difference between the highest and lowest value

4. The middle value when arranged in order

The correct answer is: The number that occurs most frequently

The mode in a set of numbers is defined as the number that occurs most frequently within that set. This means that when you analyze the data, the mode is the value that appears more times than any other. For example, in the set of numbers {2, 3, 4, 4, 5}, the number 4 is the mode because it occurs twice, whereas all other numbers occur only once. Understanding the mode is essential in statistics, particularly when trying to identify trends or common values in a data set. It can be especially useful when the data set is skewed, as the mode can highlight the most common outcome even if the average (mean) may not accurately reflect the dataset's tendencies due to extreme values. The other choices refer to different statistical concepts: the average relates to the mean, the range describes the difference between the highest and lowest values in a set, and the median refers to the middle value when numbers are arranged in ascending or descending order. Each of these terms serves a distinct purpose in data analysis, emphasizing the importance of knowing how to identify and differentiate between them.