How is the average (mean) of a data set defined?

• A. The maximum value in the data set.
• B. The middle value after ordering the data.
• C. The sum of a group of numbers divided by the number of units.
• D. The smallest value in the data set.

Answer: (C)

The mean (average) is defined as the sum of all values in a data set divided by how many values there are. This makes the mean a central value that represents the overall level of the data by spreading the total evenly across all observations. For example, with numbers 2, 4, and 6, the sum is 12 and there are 3 values, so the mean is 12 ÷ 3 = 4. The other descriptions correspond to different concepts: the maximum is the largest value, the middle value after ordering is the median, and the smallest value is the minimum. These are not the mean, which is specifically the total divided by count.