What is a prerequisite for calculating the mean of a dataset?

Calculating the mean of a dataset requires that all values involved in the calculation be numerical. The mean, which is the average value, is computed by adding together all the numerical values and then dividing by the number of values. If any of the values are non-numerical (such as text or categorical data), it would not be possible to perform the arithmetic operations necessary to find the mean.

Other options do not present prerequisites for calculating the mean. For instance, having all values the same or an odd number of values isn't necessary for mean calculation; you can have a dataset with any values, including even numbers of entries, and the values do not need to be arranged in any specific order.