std
Gets a field name for a $group operation representing the sample standard deviation of the values of the given expression when applied to all members of the group.
Use if the values encompass the entire population of data you want to represent and do not wish to generalize about a larger population.
Return
the field @mongodb.driver.manual reference/operator/aggregation/stdDevPop/ $stdDevPop @mongodb.server.release 3.2
Parameters
property
The data class property
expression
the expression