approxQuantile give incorrect Median in Spark (Scala)?

Question

I have this test data:

 val data = List(
        List(47.5335D),
        List(67.5335D),
        List(69.5335D),
        List(444.1235D),
        List(677.53         


        

Answer 1

I encountered this similar problem when trying to use the approxQuantile() method with Spark-2.2.1. When I upgraded to Spark-2.4.3, approxQuantile() now returns the right exact median.