The MEAN function is specifically designed to compute the average of a list of numbers within a DATA step in SAS. When you use the MEAN function, it calculates the sum of the values provided and then divides that sum by the count of the values, which is precisely how the mean is defined mathematically.
This function is particularly useful in data analysis and manipulation where you need to derive average values directly within the DATA step. You can pass multiple arguments to the MEAN function or even a range of variables, making it versatile for different data scenarios.
In contrast, the other functions listed do not compute the mean in the DATA step context. AVG may be associated with SQL procedures for calculating averages but is not a function used directly within the SAS DATA step. SCORE and CALCULATE do not exist as standard functions in SAS for calculating mean values. Therefore, when tasked with computing the mean in a DATA step, MEAN is the correct and appropriate function to use.