Which of the following is NOT a method to calculate an average?

The correct answer is D, as division itself is not a method to calculate an average but rather a mathematical operation that can be used in the calculation of some averages.

In the context of calculating an average, the arithmetic mean, median, and mode are all recognized statistical measures. The arithmetic mean, often referred to simply as "mean," is calculated by summing all values and dividing by the number of values. The median is the middle value in a sorted list of numbers and provides a measure of central tendency that is not affected by outliers. The mode identifies the value that appears most frequently in a data set.

While division is an essential part of finding an average—particularly in the calculation of the arithmetic mean—it is not a standalone method for calculating an average like the other three options. Therefore, the identification of division as not being a specific method for calculating an average is accurate.