When calculating the mean of a data set, what is the first step?

To calculate the mean of a data set, the first step is to add all the numbers together. The mean, also known as the average, is found by summing all the values in the data set and then dividing that total by the number of items in the set. This process begins with the addition, as it is critical to have a complete total before proceeding to determine how many items contributed to that total.

Counting the items in the data set is important, but it comes after you have summed the values, since you need the total number of items to calculate the mean accurately. The median and mode are measures of central tendency too, but they focus on different aspects of the data set and are not involved in calculating the mean. Therefore, starting with the addition of all numbers is the foundational first step in finding the mean.