"Median" field using the new Query Formula Fields

rvalenzTo ensure order I recommend breaking the solution into 2 formula queries.
1) A rank order query can be constructed with something like this in the target table: 

Size(GetRecords("{3.LTE." & [Record ID#] & "})) 

This example ranks each record, where the lowest record ID gets a return value of 1, but you could use a similar approach on any fields.

2) A formula to find the median based on rank order (doesn't need to live in target table, but can):

// Number of records where the target field is not missing
var number n = Size(GetRecords("{3.XEX.}"));

// Middle index when n is an odd number
var number i = Round($n / 2);

// Lower and upper bounds for middle ranks of the target variable
var number lb = SumValues(GetRecords("{6.EX." & $i & "}"), 3);
var number ub = SumValues(GetRecords("{6.EX." & ($i + 1) & "}"), 3);

If(Mod($n, 2) = 1, 
    $lb, // n is odd
    ($lb + $ub) / 2) // n is even, so sum 2 middlest records and divide by 2