AVERAGEX Calculates the average (arithmetic mean) of a set of expressions evaluated over a table.
Syntax
AVERAGEX(table,expression)
Parameters
table – Name of a table, or an expression that specifies the table over which the aggregation can be performed.
expression – An expression with a scalar result, which will be evaluated for each row of the table in the first argument.
Return Value
A decimal number.
Reference Data
https://docs.microsoft.com/en-us/dax/dax-function-reference