The MEAN function returns a numeric value that is the arithmetic mean (average) of its arguments. The type of this function
is numeric.

- Argument-1 must be class numeric.

- The returned value is the arithmetic mean of the argument-1 series.
- The returned value is defined as the sum of the argument-1 series divided by the number of occurrences referenced by argument-1.
- Floating-point format is used for numeric non-integer results.