How is the mean calculated?

The mean is calculated by dividing the sum of all values in a data set by the total number of values in that set. This method provides a measure of central tendency that reflects the overall average of the dataset. To compute the mean, you first gather all the values, add them together to obtain a total sum, and then divide this sum by the number of values.

This approach is foundational in statistics as it gives a true representation of the data's central location, considering all values equally. The other methods mentioned focus on different statistical measures: selecting the highest value represents the mode of a dataset, averaging the two middlemost values pertains to the calculation of the median, and counting the most frequent value also refers to the mode. None of these provide the same comprehensive average as the mean does, thus cementing option B as the correct method for calculating the mean.