Which measure of central tendency is calculated by adding all numbers and dividing by the count?

The mean is the measure of central tendency that is calculated by adding all the numbers in a dataset and then dividing this sum by the total count of the numbers. This provides a mathematical average, which serves as a representative value of the dataset. The mean is particularly useful for datasets without extreme outliers, as it takes all values into account and provides a comprehensive overview of the data's overall distribution.

In contrast, the mode refers to the value that appears most frequently in a dataset, while the median is the middle value when the numbers are arranged in order. The percentile, on the other hand, is a measure that indicates the relative standing of a value within a dataset and is used to understand distribution across different points, but it does not involve a straightforward summation and division like the mean. Thus, the correct understanding of how to calculate the mean highlights its distinct approach to summarizing data.