When using two numerical fields to generate a scatter plot, the y-axis label does not appear unless “Aggregate” is selected. This means that in order to show the label, you have to select “Group by…” and choose a unique field (because you don’t want things to be grouped) and then select Aggregate, which results in the y-axis label being prepended with an aggregation method (Sum, Min, Max, or Mean), which is not an accurate portrayal of the data that is being charted. The label should simply show up without any aggregation and just contain the name of the field.